|Moths, butterflies and allies
Fossil range: 199–0 Ma Jurassic – Recent
|A Giant Leopard Moth (Hypercompe scribonia)|
Lepidoptera (pronounced /ˌlɛp.ɪ.ˈdɒp.tər.ə:/) is a large order of insects that includes moths and butterflies (called lepidopterans). It is one of the most speciose orders in the class Insecta, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies and found virtually everywhere. Lepidoptera contains more than 180,000 species in 128 families and 47 superfamilies. The name is derived from Ancient Greek λεπίδος (scale) and πτερόν (wing). Estimates of species suggest that the order may have more species and is among the four largest, successful orders, along with the Hymenoptera, Diptera, and the Coleoptera.
Species of the order Lepidoptera are commonly characterized as being covered in scales, having two large compound eyes, and a elongated mouthpart called a proboscis. Almost all species have membranous wings, except for a few who have crossvein wings. The larvae are completely different in form, having a cylindrical body with a well developed head, mandible mouthparts, and from 0–11 (usually 8)legs.
The Lepidoptera have, over millions of years, evolved a wide range of wing patterns and coloration ranging from drab moths akin to the related order Trichoptera to the brightly colored and complex-patterned butterflies. Accordingly, this is the most recognized and popular of insect orders with many people involved in the observing, study, collecting, rearing and commerce of these insects. A person who collects or studies this order is referred to as a lepidopterist. Many species of the order are of economic interest by virtue of the silk they produce, or being pests, or due to the pollination they carry out.
The word Lepidoptera comes from the Latin word for "scaly wing", from the Ancient Greek λεπίδος (Lepidos) meaning scale and πτερόν (pteron) meaning wing. Sometimes the term Rhopalocera is used to group the species that are butterflies, from the Ancient Greek ῥόπαλον (Rhopalon) and κέρας (kæras) meaning club and horn respectively; coming from the shape of the antennae of butterflies.
The origins of the common names of many species vary. The English word butterfly is from Old English buttorfleoge, with many variations in spelling. Other than that, the origin is unknown, however it could be derived from the pale yellow color of many species' wings (eg., Yellow Sulfur: Pieridae) suggests the color of butter.(butterfly) The species of Heterocera are commonly called moths. The origins of the English word moth are more clear, which comes from Old English "moððe" (cf. Northumbrian "mohðe") from Common Germanic (compare Old Norse "motti", Dutch "Mot" and German "Motte" all meaning "moth"). Perhaps its origins are related to Old English "maða" meaning "maggot" or from the root of "midge" which until the 16th century was used mostly to indicate the larva, usually in reference to devouring clothes.(moth)
Out of the more than 180,000 species described to date can be found virtually everywhere. Some 11,300 species are from North America, and 10,000 from Australia. Lepidoptera are found in a large variety of habitats, but almost always associated with higher plants, especially angiosperms (flowering plants).
As in all insects, all species of Lepidoptera have an exoskeleton and segmented into three parts (head, thorax, abdomen) with scales and three pairs of legs. They also have two large compound eyes and an elongated mouthpart called a proboscis. Almost all species have membranous wings, except for a few who have crossvein wings. The larva are completely different in form, having a soft body with a well developed head, mandible mouthparts, and up to 11 pairs of legs (usually 8).
The adult head is segmented into six segments, though controversial, and covered with hair-like scales. Lepidoptera have a long proboscis curled under their head, and have large compound eyes which cover much of their head. Lepidoptera have long, segmented antennae that act as olfactory organs. Lepidoptera antennae also have a Johnston's organ, a collection of sensory cells found in the pedicle (or second segment) of the antennae which perceives stretching between the pedicel and the rest of the antenna. In the case of Monarch butterflies, it has been shown that antennae are necessary for proper time-compensated Sun compass orientation during migration, that antennal clocks exist in monarchs, and that they likely provide the primary timing mechanism for Sun compass orientation. In moths, males frequently have more feathery antennae than females, for detecting the female pheromones at a distance.
The thorax contains much of the insects means of locomotion, such as the legs and the wings. The thorax consists of three invisibly divided segments, namely the prothorax, metathorax and mesothorax. Adults have two pairs of membranous wings covered, usually completely, by minute scales. In some species, wings are reduced or absent (often in the female but not the male). The Trichoptera (caddisflies) which are a sister group of the Lepidoptera have scales, but also possess caudal cerci on the abdomen, a feature absent in the Lepidoptera.
The abdomen comprises about 9 segments, from segment 5 to 13 in larvae. The eleventh segment of the larvae holds the anal clasps which are represented as the genitalia which protrudes in the case of some taxa.
The compound eyes two large eyes made of a large number of hexagonal facets, or lenses, where each is connected to a lens-like cylinder that are attached to nerves leading to the brain. Each facet subtends and forms the part of an ommatidium, or cluster of photoreceptor cells.
The digestive system of Lepidoptera consists of the proboscis, leading to the esophagus or gullet, and the stomach, over which is a large, bladder-like vessel called the proventriculus, a sort of crop preceding the true stomach, which is a cylindrical tube; the intestine is a slender tube (varying in shape in different genera) divided into the small intestine, the colon, and the rectum.
Short generational lifespans in insects, such as having more than one generation per year, is associated with morphological change between generations as the abiotic factors that affect each generation, or even each reproductive change, are significantly qualitatively different. Lepidoptera typically have short lifespans, some species such as the Large White (Pieris brassicae) having upto four generations in a single year.:17 The order exhibits a wide variety of morphological forms or morphs.:163 In Lepidoptera, polymorphism can be seen between the two sexes, termed as sexual dimorphism, between individuals in a population extant at the same time, between geographically separated populations and also between generations flying at different seasons of the year. It also includes the phenomenon of mimicry when mimetic morphs fly alongside non-mimetic morphs in a population of a particular species.
Diffuse competition is suggested to be the mechanism causing the polymorphism of some species of noctuid and geometrid moths from Papua New Guinea. Polymorphism is seen as a device for maintaining dense populations and avoiding competition.
Genetic polymorphism occurs when the morphs are a result of genetic determination only. In the case of the Scarlet Tiger Moth Callimorpha (Panaxia) dominula (family Arctiidae), which is a diurnal moth occurs in continental Europe, western Asia and southern England, three forms occur in England : the typical homozygote; the rare homozygote (bimacula) and the heterozygote (medionigra). It was studied there by E.B. Ford, and later by P.M. Sheppard and their co-workers over many years. Data is available from 1939 to the present day, got by the usual field method of capture-mark-release-recapture and by genetic analysis from breeding in captivity. The records cover gene frequency and population-size for much of the twentieth century. In this instance the genetics appears to be simple: two alleles at a single locus, producing the three phenotypes. Total captures over 26 years 1939-64 came to 15,784 homozygous dominula (ie typica), 1,221 heterozygous medionigra and 28 homozygous bimacula. Now, assuming equal viability of the genotypes 1,209 heterozygotes would be expected, so the field results do not suggest any heterozygous advantage. It was Sheppard who found that the polymorphism is maintained by selective mating: each genotype preferentially mates with other morphs. This is sufficient to maintain the system despite the fact that in this case the heterozygote has slightly lower viability.
In Lepidoptera, sexual dimorphism is almost completely determined by genetic determination.:163
Different genotypes maintained by natural selection may also be expressed at the same time.:163 An example is the occurrence of polymorphic females or males in the case of some taxa in the Papilionidae.
Environmental polymorphism, where genetic heritability plays no role, is often termed as polyphenism. Polyphenism in Lepidoptera is commonly seen in the form of seasonal morphs especially in the butterfly families of Nymphalidae and Pieridae. The Old World pierid butterfly, the Common Grass Yellow (Eurema hecabe) has a darker summer adult morph, triggered by a long day exceeding 13 hours in duration, while the shorter diurnal period of 12 hours or less induces a fairer morph in the post-monsoon period.:164 Polyphenism also occurs in caterpillars, an example being the American Peppered Moth Biston betularia (shown below).
Wet-season form of Common Grass Yellow (Eurema hecabe) at Kolkata, India.
American Peppered Moth Caterpillars (Biston betularia) on birch (left) and willow (right), demonstrating a colour polyphenism.
Batesian and Müllerian mimicry complexes are commonly found in Lepidoptera. Genetic polymorphism and natural selection give rise to other-wise edible species (the mimic) gaining a survival advantage by resembling inedible Lepidoptera species (the model). Such a mimicry complex is referred to as Batesian and is most commonly known by the mimicry by the Viceroy butterfly of the inedible Monarch.
In Müllerian mimicry, inedible species, usually within a taxonomic order, find it advantageous to resemble each other so as to reduce the sampling rate by predators who need to learn about the insects' inedibilty. Taxa from the toxic genus Heliconius form one of the most well Müllerian complexes known. The adults of the various species now resemble each other so well that the species cannot be distinguished without close morphological observation and, in some cases, dissection and/or genetic analysis.
Species of Lepidoptera undergo Holometabolism, a form of metamorphism called complete metamorphism. Their life cycle normally consist of an egg, larva, pupa, and an imago or adult. The larvae are commonly called caterpillars, and the pupa of moths called cocoons and of butterflies called chrysalis.
Mating would begin where an adult (female or male) would attract a mate normally using visual stimuli, specially in diurnal species like most butterflies. However, most nocturnal female species (eg., moths) use pheromones instead to attract males, even sometimes from over long distances. Some species engage in a form of acoustic courtship, or attract mates using sound or vibration such as the Polka-dot wasp moth (Syntomeida epilais).
Lepidopteran usually reproduce sexually and are oviparous (egg-laying), though some species give to live birth in a process called ovoviviparity. There is a variety of difference in egg-laying and the number of eggs laid. Some species simply drop their eggs in flight (these species normally have polyphagous larvae, or eat a variety of plants eg., Hepialids and some Nymphalids) while most Lepidopteran will lay their eggs near or on the host plant that larva feed on, normally attracted by its odor. The amount of eggs laid may vary from only a few to thousands.
The larvae, or first stage in their life cycle after hatching, look very different from the adults and come in a variety of shapes and sizes. However, they are characterized by an elongated body with 0–11 abdominal legs (usually 8) and hooklets, called apical crochets, towards a well developed head with mandibles. The larvae eat every part of the plant, and are normally considered pest to their host plant; species have been found to lay their eggs on the fruit and other species lay the eggs even on clothing or fur (eg., Clothing Moths). A species of Geometridae from Hawaii has carnivorous larvae that grab and eat flies. Some species are carnivorous and others are even parasitic. The larvae develop rapidly with several generations in a year, however some species may take up to 3 years to develop.
After about 5 to 7 instars,:26–28 or molts, regualted by certain hormones like prothoracicotropic hormone stimulates the production of ecdysone, telling the insect to start molting. Then, the larva puparium, a sclerotized or hardened cuticle of the last larval instar, develops into the pupa. The pupa may be covered in silk and attached with many different types of debris or nothing at all depending on the species. The time it takes for pupae to emerge will vary between species. The adult will emerge from the pupa either by using abdominal hooks or a projection from the head.
While most Lepidoptera are terrestrial, many species of Pyralidae are truly aquatic with all stages except the adult occuring in water. Many species from other families such as Arctiidae, Nepticulidae, Cosmopterygidae, Tortricidae, Olethreutidae, Noctuidae, Cossidae and Sphingidae are aquatic or semi-aquatic.:22
Lepidopterans fly mostly by flapping their wings. In some Lepidoptera, there is sometimes a gliding component to their flight. Flight occurs either as hovering, or as forward or backward motion.
Navigation is important to Lepidoptera species, specially for those that migrate. Butterflies, who have more species that migrate, have been shown to navigate using time compensated sun compasses. They can see polarized light and therefore orient even in cloudy conditions. The polarized light in the region close to the ultraviolet spectrum is suggested to be particularly important. It is suggested that most migratory butterflies are those that belong to semi-arid areas where breeding seasons are short. The life-histories of their host plants also influence the strategies of the butterflies. Other theories include the use of landscapes. Lepidoptera may use coastal lines, mountains, but also man-made roads to orient themselves. Above sea it has been observed that the flight direction is much more accurate if the landscape on the coast is still visible.
Moths also show navigation, as seen in many studies. One study showed that many moths may use Earth's magnetic field to navigate, as a study of the stray Heart and Dart suggests. Another study, this time of the migratory behavior of the Silver Y, showed that this species, even at high altitudes, can correct its course with changing winds, and prefers flying with favourable winds, which suggests a great sense of direction. Aphrissa statira in Panama loses its navigational capacity when exposed to a magnetic field, suggesting it uses the Earth’s magnetic field.
Moths exhibit a tendency to circle artificial lights repeatedly. This suggests that these species use a technique of celestial navigation called transverse orientation. By maintaining a constant angular relationship to a bright celestial light, such as the Moon, they can fly in a straight line. Celestial objects are so far away, that even after traveling great distances, the change in angle between the moth and the light source is negligible; further, the moon will always be in the upper part of the visual field or on the horizon. When a moth encounters a much closer artificial light and uses it for navigation, the angle changes noticeably after only a short distance, in addition to being often below the horizon. The moth instinctively attempts to correct by turning toward the light, causing airborne moths to come plummeting downwards, and - at close range - which results in a spiral flight path that gets closer and closer to the light source.
Other explanations have been suggested, such as the idea that moths may be impaired with a visual distortion called a Mach band by Henry Hsiao in 1972. He stated that they fly towards the darkest part of the sky in pursuit of safety and are thus inclined to circle ambient objects in the Mach band region.
Lepidopteran migration is usually seasonal, moving to escape dry seasons or other disadvantageous conditions. Most lepidopteran that migrate are butterflies, varying from short to over long distances. Some butterflies that migrate include the Mourning Cloak, Painted Lady, American Lady, Red Admiral, and the Common Buckeye.:29–30 Particularly famous migrations are those of the Monarch butterfly from Mexico to northern USA and southern Canada, a distance of about 4000 to 4800 km (2500–3000 mi). Other well known migratory species include the Painted Lady and several of the Danaine butterflies. Spectacular and large scale migrations associated with the Monsoons are seen in peninsular India. Migrations have been studied in more recent times using wing tags and also using stable hydrogen isotopes.
Moths also undergo migrations, such as the uraniids. U. fulgens undergoes population explosions and massive migrations that may be not surpassed by any other insect in the Neotropics. In Costa Rica and Panama, the first population movements may begin in July and early August and, depending on the year, may be very massive, continuing unabated for as long as five months.
Pheromones are commonly involved in mating rituals amongst species, specially moths. However, pheromones appear in other forms of communication amongst species as an important form of communication. Usually only one sex will produce the pheromones and the other would pick them up with it's antennae. In many female species, a gland between the eighth and ninth segment under the abdomen produces the pheromones.
Communication can also occur through stridulation, or producing sounds by rubbing various parts of the body together. Some species engage in a form of acoustic courtship, or attract mates using sound or vibration such as the Polka-dot wasp moth (Syntomeida epilais).
Lepidopterans are soft bodied and move slowly, therefore at risk to predators including birds, wasps, and mammals. Some caterpillars, such as the zebra swallowtail butterfly larvae, are cannibalistic and may eat other larvae of the same species. Wasps and flies may lay eggs in the caterpillar which would eventually kill it as they hatch inside its body and eat its tissues. Butterflies are more fragile and almost defenseless. Lepidopterans rely on a variety of strategies for defense and protection.
Some species of lepidoptera are poisonous to predators, such as the monarch butterfly and pipevine swallowtail butterfly. They obtain their toxicity from the plants they eat. The brightly colored caterpillars and adults are generally the toxic ones, giving their color a reminder to predators about their toxicity. Predators that eat poisonous lepidopterans may become sick and vomit violently, learning not to eat those types of lepidopterans. A predator who has previously eaten a poisonous lepidopteran may avoid other species with similar markings in the future, thus saving many other species as well.
Other caterpillars emit bad smells to ward off predators. Some caterpillars, especially members of Papilionidae, contain an osmeterium, a Y-shape protrusible gland found in the prothoracic segment of the larvae. When threatened, the caterpillar emits unpleasant smells from the organ to ward off the predators.
Camouflage and mimicry are also important defense strategies. Some lepidopterans blend with its surroundings, making them difficult to be spotted by predators. Caterpillars can be shades of green that matches its host plant. Others look like inedible objects, such as the Western Tiger Swallowtail larvae that look like bird droppings. For example, adult Sesiidae species (also known as clearwing moths) have a general appearance that is sufficiently similar to a wasp or hornet to make it likely that the moths gain a reduction in predation by Batesian mimicry.
Eyespots are a type of automimicry used by some lepidopterans. In butterflies, the spots are composed of concentric rings of scales of different colors. Studies have investigated their role in defensive behavior. The proposed role of the eyespots is to deflect attention to predators. Their resemblance to eyes provokes the predator's instinct to attack these wing patterns.
Not much is known about ancient Lepidoptera species because so few fossils have been found. The earliest known Lepidopteran fossil, Archaeolepis mane is from the Jurassic period, about 190 million years ago. The fossil consists of a pair of wings with scales that are characteristically similar to the wing venation pattern found in Trichoptera (caddisflies). 2 other sets of Jurassic Lepidopteran fossils have been found, and 13 sets from the Cretaceous period.
Lepidoptera and Trichoptera (caddisflies) share many similarities that are lacking in other insect orders.
Micropterigidae, Agathiphagidae and Heterobathmiidae are the oldest and most basal lineages of Lepidoptera. The adults of these families do not have the curled tongue or proboscis that are found in most members order, but instead have chewing mandibles adapted for a special diet. Micropterigidae larvae feed on leaves, fungi, or liverworts (much like the Trichoptera). Adult Micropterigidae chew the pollen or spores of ferns. In the Agathiphagidae, larvae live inside kauri pines and feed on seeds. In Heterobathmiidae the larvae feed on the leaves of Nothofagus, the southern beech tree. These families also have mandibles in the pupal stage, which help the pupa emerge from the seed or cocoon after metamorphosis.
The Eriocraniidae have a short coiled proboscis in the adult stage, and though they retain their pupal mandibles with which they escaped the cocoon, their mandibles are non-functional thereafter. Most of these non-ditrysian families, are primarily leaf miners in the larval stage. In addition to the proboscis, there is a change in the scales among these basal lineages, with later lineages showing more complex perforated scales.
With the evolution of the Ditrysia in the mid-Cretaceous, there was a major reproductive change. The Ditrysia, which comprise 98% of the Lepidoptera, have two separate openings for reproduction in the females (as well as a third opening for excretion), one for mating, and one for laying eggs. The two are linked internally by a seminal duct. (In more basal lineages there is one cloaca, or later, two openings and an external sperm canal.) Of the early lineages of Ditrysia, Gracillarioidea and Gelechioidea are mostly leaf miners, but more recent lineages feed externally. In the Tineoidea, most species feed on plant and animal detritus and fungi, and build shelters in the larval stage.
The Yponomeutoidea is the first group to have significant numbers of species whose larvae feed on herbaceous plants, as opposed to woody plants. They evolved about the time that flowering plants underwent an expansive adaptive radiation in the mid-Cretaceous, and the Gelechioidea that evolved at this time also have great diversity. Whether the processes involved co-evolution or sequential evolution, the diversity of the Lepidoptera and the angiosperms increased together.
In the so-called "macrolepidoptera", which constitutes about 60% of Lepidopteran species, there was a general increase in size, better flying ability (via changes in wing shape and linkage of the forewings and hindwings), reduction in the adult mandibles, and a change in the arrangement of the crochets (hooks) on the larval prolegs, perhaps to improve the grip on the host plant. Many also have tympanal organs, that allow them to hear. These organs evolved eight times, at least, because they occur on different body parts and have structural differences. The main lineages in the macrolepidoptera are the Noctuoidea, Bombycoidea, Lasiocampidae, Mimallonoidea, Geometroidea and Rhopalocera. Bombycoidea plus Lasiocampidae plus Mimallonoidea may be a monophyletic group. The Rhopalocera, comprising the Papilionoidea (Butterflies), Hesperioidea (skippers), and the Hedyloidea (moth-butterflies), are the most recently evolved. There is quite a good fossil record for this group, with the oldest skipper about 56 million years old.
The characteristics which distinguish the order Lepidoptera from other insect orders are:
Linnaeus in Systema Naturae (1758) recognized three divisions of the Lepidoptera: Papilio, Sphinx, and Phalaena with seven subgroups in Phalaena. These persist today as 9 of the superfamilies of Lepidoptera. Other works on classification followed including those by Denis & Ignaz Schiffermüller (1775), Fabricius (1775) and Pierre André Latreille (1796). Jacob Hübner described many genera, and the Lepidopteran genera were catalogued by Ochsenheimer and Treitschke in a series of volumes on the Lepidopteran fauna of Europe published between 1807 and 1835. G.A.W. Herrich-Schaffer (several volumes, 1843-1856), and Edward Meyrick (1895) based their classifications primarily on wing venation. Sir George Francis Hampson worked on the 'microlepidoptera' during this period and Philipp Christoph Zeller published The Natural History of the Tineinae13 volumes also on 'microlepidoptera'(1855).
Among the first entomologists to study fossil insects and their evolution was Samuel Hubbard Scudder (1837-1911), who worked on butterflies. He published a study of the Florissant deposits of Colorado. Andreas V. Martynov (1879-1938) recognized the close relationship between Lepidoptera and Trichoptera in his studies on phylogeny. Lepidoptera tend not to be as common as some other insects in the habitats that are most conducive to fossilization, such as lakes and ponds, and their juvenile stage has only the head capsule as a hard part that might be preserved. Yet there are fossils, some preserved in amber and some in very fine sediments. Leaf mines are also seen in fossil leaves, although the interpretation of them is tricky. The earliest fossil is Archaeolepis mane from the Jurassic, about 190 million years ago in Dorset, UK. It consists of wings and shows scales with parallel grooves under a scanning electron microscope and the characteristic wing venation pattern shared with Trichoptera. Only 2 more sets of Jurassic Lepidopteran fossils have been found, and 13 sets in the Cretaceous. From there, many more fossils are found from the Tertiary, and particularly the Eocene Baltic amber.
Major contributions in the 20th century included the creation of the monotrysia and ditrysia (based on female genital structure) by Borner in 1925 and 1939. Willi Hennig (1913-1976) developed the cladistic methodology and applied it to insect phylogeny. Niels P. Kristensen, E. S. Nielsen and D. R. Davis studied the relationships among monotrysian families and Kristensen worked more generally on insect phylogeny and higher Lepidoptera too.. While it is often found that DNA-based phylogenies differ from those based on morphology, this has not been the case for the Lepidoptera; DNA phylogenies correspond to a large extent to morphology-based phylogenies.
Many attempts have been made to group the superfamilies of the Lepidoptera into natural groups, most of which fail because one of the two groups is not monophyletic: Microlepidotera and Macrolepidoptera, Heterocera and Rhopalocera, Jugatae and Frenatae, Monotrysia and Ditrysia.
Artistic depictions of butterflies have been used in many cultures including as early as 3500 years ago, in Egyptian hieroglyphs. Today, butterflies are widely used in various objects in art and jewelry: mounted in frames, embedded in resin, displayed in bottles, laminated in paper, and in some mixed media artworks and furnishings. Butterflies have also inspired the "butterfly fairy" as an art and fictional character, including in the Barbie Mariposa film.
In many cultures the soul of a dead person is associated with the butterfly. As in Ancient Greece, where the word for butterfly ψυχή (psyche) also means soul and breathe. In Latin, as in Ancient Greece, the word for butterfly papillio was associated with the soul of the dead.
The Death's-head Hawkmoth's skull pattern on its thorax has helped these moths, particularly A. atropos, earn a negative reputation, such as associations with the supernatural and evil. The moth has been prominently featured in art and movies such as Un Chien Andalou (by Buñuel and Dalí) and The Silence of the Lambs, and in the artwork of the Japanese metal band Sigh's Hail Horror Hail album.
Species of Lepidoptera are major pest in agriculture, particularly the larvae. Many species cause damage, some of the major include Tortricidae, Noctuidae, and Pyralidae; some particular species of concern also include those of the Noctuidae genus Spodoptera (armyworms) and Helicoverpa (corn earworm). Helicoverpa zea larvae are polyphagous, meaning they eat a verity of crops. The larvae are commonly called mattering on what they are eating, for example if they are eating corn they are called corn earworm. Other common crops they consume are tomatoes, then called tomato fruitworm, and cotton, then called a cotton bollworm.
Most species of Lepidoptera engage in the pollination of flowers. The adults feed on the nectar inside flowers, using their proboscis to reach the nectar hidden at the base of the petals. In the process, the adult brushes against the flower's stamen, on which the flower's reproductive pollen is made and stored. The pollen is transferred to the adult, who flies to the next flower to feed and unwittingly deposits the pollen on the stigma of the next flower, where the pollen germinates and fertilizes the seeds.
The larvae of Bombyx mori are more commonly known as silkworms. They make their cocoons out of silk which can be spun into cloth. Silk is and has been an important economic resource throughout history. The species Bombyx mori has been domesticated to the point where it is completely dependent on humans for survival. On the other hand, the species Bombyx mandarina, or "Wild Silkmoth," lives and produces silk naturally.
Lepidoptera feature prominently in entomophagy as food items on almost every continent. While in most cases, adults, larvae or pupae are eaten as staples by indigenous people, beondegi or silkworm pupae are eaten as a snack in Korean cuisine while Maguey worm is considered a delicacy in Mexico.. In the Carnia region of Italy, children catch and eat Zygaena moths in early summer. The ingluvies, despite having a very low cyanogenic content, serves as a convenient, supplementary source of sugar to the children who can include this resource as a seasonal delicacy at minimum risk.
LEPIDOPTERA (Gr. Xc ris, a scale or husk, and 71-mpbv, a wing), a term used in zoological classification for one of the largest and best-known orders of the class Hexapoda, in order that comprises the insects popularly called butterflies and moths. The term was first used by Linnaeus (1735) in the sense still accepted by modern zoologists, and there are few After Edwards, Riley and Howard's Insect Life, vol. 3 (U.S. Dept. Age.).
FIG. 1. - e, Crytophasa unipuctata, Donov., Australia. a, Larva; c, pupa, natural size; b, 2nd and 3rd abdominal segments of larva; d, cremaster of pupa, magnified.
groups of animals as to whose limits and distinguishing characters less controversy has arisen.
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The name of the order indicates the fact that the wings (and other parts of the body) are clothed with flattened cuticular structures - the scales (fig. 7) - that may be regarded as modified arthropodan " hairs." Such scales are not peculiar to the Lepidoptera - they are found also on many of the Aptera, on the Psocidae, a family of Corrodentia, on some Coleoptera (beetles) and on the gnats (Culicidae), a family of Diptera. The most distinctive structural features of the Lepidoptera are to be found in the jaws. The mandibles are mere vestiges or entirely absent; the second maxillae are usually reduced to a narrow transverse mentum which bears the scale-covered labial palps, between which project the elongate first maxillae, grooved on their inner faces, so as to form when apposed a tubular proboscis adapted for sucking liquid food.
All Lepidoptera are hatched as the eruciform soft-bodied type of larva (fig. i, a) known as the caterpillar, with biting mandibles, three pairs of thoracic legs and with a variable number (usually five pairs) of abdominal prolegs, which carry complete or incomplete circles of hooklets. The pupa in a single family only is free (i.e. with the appendages free from the body), and mandibulate. In the vast majority of the order it is more or less obtect (i.e. with the appendages fixed to the cuticle of the body) and without mandibles (fig. 1, c). Structure. - The head in the Lepidoptera is sub-globular in shape with the compound eyes exceedingly well developed, and with a pair of ocelli or " simple eyes " often present on the vertex. It is connected to the thorax by a relatively broad and membranous " neck." The feelers are many-jointed, often they are complex, the segments bearing processes arranged in a comb-like manner and furnished with numerous sensory hairs (fig. 2). The complexity of the feelers is carried to its highest development in certain male moths that have a wonderful power of discovering their a females by smell or some analogous sense. Often the feelers are excessively complex in male moths whose Naturw. vol. 18).
FIG. 3. - A, Mandible, and B, 1st maxilla of Micropteryx (Eriocephala). Magnified.
a, Palp. d, Stipes.
b, Galea. e, Cardo of c, Lacinia. maxilla.
able number of Lepidoptera take no food in the imaginal state; in these the maxillae are reduced or altogether atrophied. The second maxillae are intimately fused together to form the labium, which consists only of a reduced mentum, bearing sometimes vestigial lobes and always a pair of palps. These have two or three segments and are clothed with scales. m ,P The form and direc tion of the terminal 1 r'=, p $ segment of the labial _ palp afford valuable characters in classification.
In the thorax of the Lepidoptera the foremost segment or A..,?
small, and is very =E *' `, small, .d not mov able on the mesoL thorax. In many ® r families it carries a pair of small erectile ,` " 's,....;... r plates - the patagia - which have been regarded as serially homologous with the wings. The mesothorax is extensive; its scutum forming most of the dorsal thoracic area and small plates - tegulae - are often present at the base of the forewings, as in Hymenoptera. The tegulae which are beset with long hair-like scales are often conspicuous. The metathorax is smaller than the mesothorax. The legs are of the typical hexapodan form with five-segmented feet; the shins often bear terminal and median spurs articulated at their bases and the entire limbs are clothed with scales.
The wings of the Lepidoptera may be said to dominate the structure of the insect; only exceptionally, in certain female moths, are they vestigial or absent (fig. 17). The forewing, with its prominent apex, is longer than the hindwing, and the 2 3, neuration in both (see figs. 5 and 6) is for the most part longitudinal, only a few transverse ner- ` f 3,7 v..res, which are, in 2 4, fact, branches of the S? 4 median trunk, a marking off a discoidal areolet or " cell " (fig. 5, a). 2 The five branches of the radial nervure 3 (figs. 5, 6, 3) (see ?.
Hexapoda) are usually present in 3 3s a the forewing, but g r the hindwing, in After A. S. Packard, Mem. Nat, Acad. Sci. vol. vii, most families, has only a single radial nervure; its anal area is, however, often more strongly developed than that of the forewing. The two wings of a side are usually kept together during flight by a few stout bristles - the frenulum - (fig. 5, f) projecting from the base of the costa of the hindwing and fitting beneath a membranous fold or a few thickened scales - the retinaculum - on the under surface of the forewing. In butterflies there is no frenulum, but a costal outgrowth of the From Riley and Howard, Insect Life, vol. 7 (U.S. Dept. Agr.).
FIG. 2. - a, Feeler of Saturniid Moth (Telex Polyphemus), magnified 3 times. b, c, Tips of branches, highly magnified. maxillae are so re duced that they take no food in the imaginal state. The nature of the jaws has already been briefly described. Functional mandibles of peculiar form (fig. 3, A) are present in the remarkable small moths of the genus Micropteryx (or Eriocephala), and there are vestiges of these jaws in other moths of low type, but the minute structures in the higher Lepidoptera that were formerly described as mandibles are now believed to belong to the labrum, the true mandibles being perhaps represented by rounded prominences, not articulated with the head-capsule. Throughout the order, as a whole, the jaws are adapted for sucking liquid food, and the suctorial proboscis (often erroneously called a g " tongue ") is formed as was shown by J. C. Savigny in 1816 by two elongated and flexible outgrowths of the first maxillae, usually regarded as representing the outer lobes or galeae (fig. 4, A, B, g). These structures are grooved along their inner faces and by means of a series of interlocking hair-like bristles can be & joined together so as to form a tubular sucker (fig. 4, C). At their extremities they are beset with clublike sense-organs, whose apparent function is that of taste. The proboscis when in use is stretched out in front of the head and inserted into the corolla of a flower or elsewhere, for the absorption of liquid nourishment. When at rest, the proboscis is rolled up into a close spiral beneath the head and between the labial palps (fig. 4, A, p). Only in the genus Micropteryx mentioned above is the lacinia of the maxilla (as A. Walter has shown) developed (fig. 3, B, c). The maxillary palp is usually a mere vestige (fig. 4, B, p) though it is conspicuous in a few families of small moths. A consider Afte r A. Walter (Jen. Zeits. f, C FIG. 4. - Arrangement of the jaws in a typical Moth. Somewhat diagrammatic and in part after E. Burgess and V. L. Kellogg (Amer. Nat. xiv. xxix.).
A, Front view of head.
e, Compound eye.
m, Vestigial mandible.
g, Galeae of 1st maxillae.
p, Labial palp. Magnified, B. [head. b, Base of first maxilla dissected out of the p, Vestigial pale.
g, Galea. Further magnified.
C, Part transverse section showing how the channel (A) of the proboscis is formed by the interlocking of the grooved inner faces of the flexible maxillae.
FIG. 5. - Wing-neuration of a Notodont Moth. 2, Subcostal; 3, radial; 4, median; 5, cubital; 7, 8, anal nervures. a, Discoidal areolet or " cell "; f, frenulum. Note that the forewing has five branches (1-5) of the radial nervure, the hindwing one only. The first anal nervure (No. 6) is absent.
hindwing subserves the same function. In the most primitive moths a small lobate outgrowth - the jugum (fig. 6, j.) - from the dorsum of the forewing is present, but it can be of little service in keeping the two wings together. A jugum may be also present on the hindwing. The legs, which are generally used for clinging rather than for walking, have five-segmented feet and are covered with scales. In some families the front pair are reduced and without tarsal segments.
Ten abdominal segments are recognizable in many Lepidoptera, but the terminal segments are reduced or modified to form external organs of reproduction. In the male, according to the interpretation of C. Pey 3 toureau, the lateral plates belonging to the ninth seg ment form paired claspers beset with harpes, or series of ridges or teeth, while the tergum of the tenth segment forms a dorsal hook - the uncus - and its sternum a ventral process or scaphium. In the female the terminal segments form, in some cases, a protrusible ovipositor, but the typical hexapodan ovipositor with its three pairs of processes is undeveloped in the Lepidoptera.
As already mentioned, the characteristic scales on the wings, legs and body of the Lepidoptera are cuticular structures. A complete series of transitional forms can be traced between the most elaborate flattened scales (fig. 7, B) with numerous longitudinal striae and a simple arthropod " hair." Either a " ` hair " or a scale owes its origin to a special cell of the ectoderm (hypodermis), a process from which grows through the general cuticle and forms around itself the substance of the cuticular appendage. The scales on the wings are arranged in regular rows (fig. 7, A), and the general cuticle is drawn out into a narrow neck or collar around the base of each scale. The scales can be easily rubbed from the surface of the wing, and the series of collars in which the scales rest are then evident (fig. 7, A, c) on the wing-membrane. On the wings of many male butterflies there are specially modified scales - the androconia (fig. 7, C) - which are formed by glandular cells and diffuse a scented secretion. In some cases, the androconia are mixed among the ordinary scales; in others they are associated into conspicuous " brands " (see fig. 66). The admirable colours of the wings of the Lepidoptera are due partly to pigment in the scales - as in the ease of yellows, browns, reds and blacks - partly to " interference " effects from the fine striae on the scales - as with the blues, purples and greens.
A few points of interest in the in- " n ternal structure of the Lepidoptera deserve mention. The mouth opens into a sub-globular, muscular pharynx which is believed to suck the liquid food through the proboscis, and force it along the slender gullet into a croplike enlargement or diverticulum of the fore-gut known as a " food-reservoir " or " sucking-stomach." The true stomach is tubular, anu beyond it lies the intestine into which open the three pairs of excretory (Malpighian) tubes. The terminal part of the intestine is of wide diameter, and in some cases gives off a short caecum. The brain and the sub-oesophageal ganglia are closely approximated; there are two or three thoracic and four (rarely five) abdominal ganglia. In the female each ovary has four ovarian tubes, in which the large egg-cells are enclosed in follicles and associated with nutritive cells. There is a special bursa which in the Hepialidae opens with the vagina on the eighth abdominal sternum. In the Micropterygidae, Eriocraniidae and the lower Tineides, the duct of the bursa leads into the vagina, which still opens on the eighth sternum. But in most Lepidoptera, the bursa opens by a vestibule on the eighth sternum, distinct from the vagina, whose opening shifts back to the ninth, the duct of the bursa being connected with the vagina by a canal which opens opposite to the spermatheca. In the male, the two testes are usually fused into a single mass, and a pair of tubular accessory glands open into the vasa deferentia or into the ejaculatory duct. In a few families - the Hepialidae and Saturniidae for example - the testes retain the primitive paired arrangement. These details have been worked out by various students, among whom W. H. Jackson and W. Petersen deserve special mention. Summing up the developmental history of the genital ducts, Jackson remarks that there is " an Ephemeridal stage, which ends towards the close of larval life, an Orthopteran stage, indicated during the quiescent period preceding pupation, and a Lepidopteran stage which begins with the commencement of pupal life." Development - Many observations have been made on the embryology of the Lepidoptera; for some of the more important FIG. 8 A. - Cossus macmurtrei. r (MacMurtrie's Goat Moth.) N. America.
results of these see Hexapoda. The post-embryonic development of Lepidoptera is more familiar, perhaps, than that of any other group of animals. The egg shows great variation in its outward form, the outer envelope or chorion being in some families globular, in others flattened, in others again erect and sub-conical or cylindrical; while its surface often exhibits a beautifully regular series of ribs and furrows. Throughout the order the larva is of the form known as the caterpillar (fig. i, a, b, fig. 8 B) FIG. 8 B. - Larva of Cossus cossus. (Goat Moth.) Europe.
characterized by the presence of three pairs of jointed and clawed legs on the thorax and a variable number of pairs of abdominal " prolegs " - sub-cylindrical outgrowths of the abdominal segments, provided with a complete or incomplete circle of hooklets at the extremity.
There are ten abdominal segments - the ninth often small and concealed; prolegs are usually present on the third, fourth, fifth, sixth and tenth of these segments. The head of the caterpillar (fig. 9) is large with firmly chitinized cuticle; it carries usually twelve simple eyes or ocelli, a pair of short feelers (fig. 9 At) and a pair of strong mandibles (fig. 9, Mn), for the caterpillar feeds by biting leaves or other planttissues. The first maxillae, so highly developed in the imago, are in the larva small and inconspicuous appendages, each bearing two short jointed processes, - the galea and the palp (fig. 9, Mx). The second maxillae form a plate-like labium on whose surface projects the spinneret which is usually regarded as a modified hypopharynx (fig. 9, FIG. 9. - Head of Goat Moth Lm). The silk-glands whose ducts Caterpillar (Cossus) from beopen on this spinneret are paired hind. Magnified. (From Miall convoluted tubes lying alongside and Denny after 14yonnet.) the elongate cylindrical stomach. At, Feeler.
In the common " silkworm " these Mn, Mandible.
glands are five times as long as the Mx, First maxilla.
body of the caterpillar. They are re- Lm, Second maxillae (Labgarded as modified salivary glands, ium) with spinneret. though the correspondence has been doubted by some students. The body of the caterpillar is usually cylindrical and wormlike, with the 5 After Packard, Mem. Nat. Acad. Sci. vol. vii.
FIG. 6. - Wing neuration of a Swift Moth (Hepialid). j, Jugum. Nervures numbered as in fig. 5. Note that there are five branches to the radial nervure (No. 3) in both foreand hindwing, and that the median trunk nervures (No. 4) traverse the discoidal areolet.
B FIG. 7. - A, Arrangement of scales in rows on wing of Butterfly. n, Nervure; c, collar-like outgrowths of cuticle. Magnified. B, single scale, and C, an androconium more highly magnified.
segmentation well marked and the cuticle feebly chitinized and flexible. Firm chitinous plates are, however, not seldom present on the prothorax and on the hindmost abdominal segment. The segments are mostly provided with bristle or spine-bearing tubercles, whose arrangement has lately been shown by H. G. Dyar to give partially trustworthy indications of relationship. On either side of the median line we find two dorsal or trapezoidal tubercles (Nos. I and 2), while around the spiracle are grouped (Nos. 3, 4 and 5) supra-, post-, and pre-spiracular tubercles; below are the subspiraculars, of which there may be two (Nos. 6, 7). The last-named is situated on the base of the abdominal proleg, and yet another tubercle (No. 8) may be present on the inner aspect of the proleg. The spiracles are very conspicuous on the body of a caterpillar, occurring on the prothorax and on the first eight abdominal segments. Various tubercles may become coalesced or aborted (fig. Io, B); often, in conjunction with the spines that they bear, the tubercles serve as a valuable protective armature for the caterpillar. Much discussion has taken place as to whether the abdominal prolegs are or are not developed directly from the embryonic abdominal appendages. In the more lowly families of Lepidoptera, these organs are provided at the extremity with a complete circle of hooklets, but in the more highly organized families, only the inner half of this circle is retained.
The typical Lepidopteran pupa, or " chrysalis," as shown in the higher families, is an obtect pupa (fig. I I) with no trace of mandibles, the appendages being glued to the body by an exudation, and B, after Grote, Mitt. alts dem Roemer Museum, No. 6.
FIG. Io. - Abdominal segments of Caterpillars, to show arrangement of tubercles; the arrows point anteriorly. A, Generalized condition; B, specialized condition in the Saturniidae. s, Spiracle; the numbering of the tubercles is explained in the text. Note that in FIG. II. - PUpa B No. 2 is much reduced and disappears of a Butterfly after the first moult. 4 and 5 are (Amathusia phi- coalesced, and 6 is absent. dippus). motion being possible only at three of the abdominal intersegmental regions, the fifth and sixth abdominal segments at most being " free." A flattened or pointed process - the cremaster - often prominent at the tail-end, may carry one or several hooks (fig. I, d) which serve to anchor the pupa to its cocoon or to suspend butterfly-pupae from their pad of silk (fig. II). In the lower families the pupa (fig. I, c) is only incompletely obtect, and a greater number of abdominal segments can move on one another. The seventh abdominal segment is, in all female lepidopterous pupae, fused with those behind it; in the male " incomplete " pupa this becomes " free " and so may the segments anterior to it, in both sexes, forward to and including the third. The presence of circles of spines on the abdominal segments enables the " incomplete " pupa as a whole to work its way partly out of the cocoon when the time for the emergence of the imago draws near. In the family of the Eriocraniidae (often called the Micropterygidae) the pupa resembles that of a caddis-fly (Trichopteron) being active before the emergence of the imago and provided with strong mandibles by means of which it bites its way out of the cocoon. The importance of the pupa in the phylogeny and classification of the Lepidoptera has lately been demonstrated by T. A. Chapman in a valuable series of papers. Sometimes organs are present in the pupa which are undeveloped in the imago, such as the maxillary palps of the Sesiidae (clearwing moths) and the pectination on the feelers of female Saturniids. E. B. Poulton has drawn attention to the ancestral value of such characters.
The attractiveness of the Lepidoptera and the conspicuous appearance of many of them have led to numerous observations on their habits. The method of feeding of the imago by the suction of liquids has already been mentioned in connexion with the structure of the maxillae and the foodcanal. Nectar from flowers is the usual food of moths and butterflies, most of which alight on a blossom before thrusting the proboscis into the corolla of the flower, while others - the hawk moths (Sphingidae) for example - remain poised in the air in front of the flower by means of excessively rapid vibration of the wings, and quickly unrolling the proboscis sip the nectar. Certain flowers with remarkably long tubular corollas seem to be specially adapted for the visits of hawk moths. Some Lepidoptera have other sources of food-supply. The juices of fruit are often sought for, and certain moths can pierce the envelope of a succulent fruit with the rough cuticular outgrowths at the tips of the maxillae, so as to reach the soft tissue within. Animal juices attract other Lepidoptera, which have been observed to suck blood from a wounded mammal; while putrid meat is a familiar " lure " for the gorgeous " purple emperor " butterfly (Apatura iris). The water:of streams or the dew on leaves may be frequently sought by Lepidoptera desirous of quenching their thirst, possibly with fatal results, the insects being sometimes drowned in rivers in large numbers. Members of several families of the Lepidoptera - the Hepialidae, Lasiocampidae and Saturniidae, for example - have the maxillae vestigial or aborted, and take no food at all after attaining the winged condition. In such insects there is a complete " division of labour " between the larval and the imaginal instars, the former being entirely devoted to nutritive, the latter to reproductive functions.
Of much interest is the variety displayed among the Lepidoptera in the season and the duration of the various instars. The brightly coloured vanessid butterflies, for example, emerge from the pupa in the late summer and live through the winter in sheltered situations, reappearing to lay their eggs in the succeeding spring. Many species, such as the vapourer moths (Orgyia), lay eggs in the autumn, which remain unhatched through the winter. The eggs of the well-known magpie moths (Abraxas) hatch in autumn and the caterpillar hibernates while still quite small, awaiting for its growth the abundant food-supply to be afforded by the next year's foliage. The codlin moths (Carpocapsa) pass the winter as resting full-grown larvae, which seek shelter and spin cocoons in autumn, but do not pupate until the succeeding spring. Lastly, many of the Lepidoptera hibernate in the pupal stage; the death's head moth (Acheronitia) and the cabbage-white butterflies (Pieris) are familiar examples of such. The last-named insects afford instances of the " double-brooded " condition, two complete life-cycles being passed through in the year. The flour moth (Ephestia kiihniella) is said to have five successive generations in a twelvemonth. On the other hand, certain species whose larvae feed in wood or on roots take two or three years to reach the adult stage.
The rate of growth of the larva depends to a great extent on the nature of its food, and the feeding-habits of caterpillars afford much of interest and variety to the student. The contrast among the Lepidoptera between the suctorial mouth of the imago and the biting jaws of the caterpillar is very striking (cf. figs. 4 and 9), and the profound transformation in structure which takes place is necessarily accompanied by the change from solid to liquid food. The first meal of a young caterpillar is well known to be often its empty egg-shell; from this it turns to feed upon the leaves whereon its provident parent has laid her eggs. But in a few cases hatching takes place in winter or early spring, and the young larvae have then to find a temporary food until their own special plant is available. For example, the caterpillars of some species of Xanthia and other noctuid moths feed at first upon willow-catkins. On the other hand, the caterpillars of the pith moth (Blastodacna) hatched at midsummer, feed on leaves when young, and burrow into woody shoots in autumn. All who have tried to rear caterpillars know that, while those of some species will feed only on one particular species of plant, others will eat several species of the same genus or family, while others again are still less particular, some being able to feed on almost any green herb. It is curious to note how certain species change their food in different localities, a caterpillar confined to one plant in some localities being less particular elsewhere. Individual aberrations in food are of special interest in suggesting the starting-point for a change in the race. When we consider the vast numbers of the Lepidoptera and the structural modifications which they have undergone, their generally faithful adherence to a vegetable diet is remarkable. The vast majority of caterpillars eat leaves, usually devouring them openly, and, if of large size, quickly reducing the amount of foliage on the plant. But many small caterpillars keep, apparently for the sake of concealment, to the under surface of the leaf, while others burrow into the green tissue, forming a characteristic sinuous " mine " between the two leaf-skins. In several families we find the habit of burrowing in woody stems, - the " goat " (Cossus, fig. 8) and the clearwings (Sesiidae), for example, while others, like the larvae of the swift moths (Hepialidae) live underground devouring roots (fig 12). The richer nutrition in the green food is usually shown by the quicker growth of the numerous caterpillars that feed on it, as compared with the slower development of the wood and root-feeding species. Aquatic larvae are very rare among the Lepidoptera. The caterpillars of the pyralid " china-mark " moths (Hydrocampa), (fig. 13), however, live under water, feeding on duckweed (Lemna) and breathing atmospheric air, a film of which is enclosed in a spun-up shelter beneath the leaves, while the larvae of Paraponyx, which feed on Stratiotes, have closed spiracles and breathe dissolved air by means of branchial filaments along the sides of the body.
FIG. 12. - Larva of Hepialus humuli (ghost moth).
We may now turn to instances of more anomalous modes of feeding. The clothes moths (Tineids) have invaded our dwellings and found a congenial food-stuff for their larvae in our garments. A few small species of the same group are reared in meal and other human food-stores; so are the caterpillars of some pyralid moths (Ephestia), while others (Asopia, Aglossa) feed upon kitchen refuse. Two species of crambid moths (Aphomia sociella and Galleria melonella) find a home in bee-hives, where their caterpillars feed upon the wax, while the waxy secretion from the body of the great American lantern-fly (Fulgora candelaria) serves both as shelter and food for the caterpillar of the moth Epipyrops anomala. Very few caterpillars have developed a thoroughly carnivorous habit. That of Cosmia trapezina feeds on oak and other leaves, but devours smaller caterpillars which happen to get in its way, and if shaken from the tree, eats other larvae while climbing the trunk. Xylina ornithopus and a few other species are said to be always carnivorous when opportunity offers; the small looping caterpillar of a " pug " moth (Eupithecia coronata) has been observed to eat a larva three times as big as itself. The caterpillars of Orthosia pistacina live together in peace while their food is moist, but devour each other when it dries up; this is true cannibalism - a term which should not be applied to the habit of preying on another species. A few carnivorous caterpillars do not attack other caterpillars, but prey upon insects of another order; among these Fenescia tarquinius, which eats aphides, and Erastria scitula, which feeds upon scale insects, must be reckoned as benefactors to mankind. The life-history of the latter moth has been worked out by H. Rouzaud. It inhabits the shores of the Mediterranean, and its caterpillar devours the coccids upon various fruit-trees, especially the black-scale (Lecanium oleae) of the olive. The moth, which is a small noctuid, the white markings on whose wings give it the appearance of a bird-dropping when at rest in the daytime, appears in May, and lays her eggs, singly and far apart, upon the trees infested by the coccids. When hatched, the young caterpillar selects a large female coccid, eats its way through the scale, and devours the insect beneath; having done this it makes its way to a fresh victim. As it increases in size it forms a case for itself made of the scales of its victims, excrement, &c., bound together by silk which it spins, and, protected by this covering, which closely resembles the smut-covered bark of the tree, it roams about during its later stages, devouring several coccids every day. So nutritious is the food, that four or five successive broods follow each other through the summer.
The habit just mentioned of forming some kind of protective covering out of foreign substances spun together by silk is practised by caterpillars of different families. The clothes moth larvae (Tinea, fig. 54), for example, make a tubular dwelling out After Marlatt (after Riley), Bull. 4, Div. Ent. U.S. Dept. Agr. FIG. 14. - Clothes Moth (Tinea pellionella), with larva in and out of_its case. Magnified.
of the pellets of wool passed from their own intestines, while the allied Tortricid caterpillars roll up leaves and spin for themselves cylindrical shelters. The habit of spinning over the food plant a protective mass of web, whereon the caterpillars of a family can live together socially is not uncommon. In the case of the small ermine moths (Hyponomeuta) the caterpillars remain associated throughout their lives and pupate in cocoons on the mass of web produced by their common labour. But the larger, spiny caterpillars of the vanessid butterflies usually scatter away from the nest of their infancy when they have attained a certain size.
Spines and hairs seem to be often effective protections for caterpillars; the experiments of E. B. Poulton and others tend to show that hairy caterpillars (fig. 15) are distasteful to birds. Many caterpillars are protected by the harmony of their general green coloration with their surroundings. When the insect attains a large size - as in the case of the hawk moth (Sphingid) caterpillars - the extensive green surface becomes broken up by diagonal dark markings (fig. 46b), thus simulating the effect of light and shade among the foliage. A remarkable result of Poulton's experiments has been the establishment of a reflex effect through the skin on the colour of a caterpillar. Some species of " loopers " (Geometridae, fig. 43) for example, if placed when young among surroundings of a certain colour, become closely assimilated thereto - dark brown among dark twigs, green among green leaves. These colour-reflexes in conjunction with the elongate twig-like shape of the caterpillars and their habit of stretching themselves straight out from a branch, afford some of the best and most familiar examples of " protective resemblance." The " terrifying attitude " of caterpillars, and the supposed resemblance borne by some of them to serpents and other formidable vertebrates or arthropods, are discussed in the article Mimicry.
The silk produced by a caterpillar is, as we have seen, often advantageous in its own life-relations, but its great use is in connexion with the pupal stage. In the life-history of many Lepidoptera, the last act of the caterpillar is to spin a cocoon which may afford protection to the pupa. In some cases this is formed entirely of the silk produced by the spinning-glands, and may vary from the loose meshwork that clothes the pupa of the FIG. 13. - Hydrocampa aquatilis (water moth).
FIG. 15. - Larva of Orgyia gonostigma. Europe.
diamond-back moth (Plutella cruciferarum) to the densely woven cocoon of the silkworms (Bombycidae and Saturniidae) or the hard shell-like covering of the eggars (Lasiocampidae). Frequently foreign substances are worked up with the silk and serve to strengthen the cocoon, such as hairs from the body of the caterpillar itself, as among the " tigers " (Arctiidae) or chips of wood, as with the timber-burrowing larva of the " goat " (Cossus) . In many families of Lepidoptera we can trace a degeneration of the cocoon. Thus, the pupae of most owl moths (Noctuidae) and hawk moths (Sphingidae) lie buried in an earthen cell. Among the butterflies we find that the cocoon is reduced to a pad of silk which gives attachment to the cremaster; in the Pieridae there is in addition a girdle of silk around the waist-region of the pupa, but the pupae of the Nymphalidae (figs. II, 65) simply hang from the supporting pad by the tail-end. Poulton has shown that the colours of some exposed pupae vary with the nature of the surroundings of the larva during the final stage.
When the pupal stage is complete the insect has to make its way out of the cocoon. In the lower families of moths it is the pupa which comes out at least partially, working itself onwards by the spines on its abdominal segments; the pupa of the primitive Micropteryx has functional mandibles with which it bites through the cocoon. In the higher Lepidoptera the pupa is immovable, and the imago, after the ecdysis of the pupal cuticle, must emerge. This emergence is in some cases facilitated by the secretion of an acid or alkaline solvent discharged from the mouth or from the hind-gut, which weakens the cocoon - so that the delicate moth can break through without injury.
As might be expected, the conditions to which larva and pupa are subjected have often a marked influence on the nature of the imago. An indifferent food-supply for the larva leads to a dwarfing of the moth or butterfly. Many converging lines of experiment and observation tend to show that cool conditions during the pupal stage frequently induce darkening of pigment in the imago, while a warm temperature brightens the colours of the perfect insect. For example, in many species of butterfly that are double-brooded, the spring brood emerging from the wintering pupae are more darkly coloured than the summer brood, but if the pupae producing the latter be subjected artificially to cold conditions, the winter form of imago results. It is usually impossible, however, to produce the summer form of the species from wintering pupae by artificial heat. From this A. Weismann argued that the more stable winter form must be regarded as representing the ancestral race of the species. Further examples of this " seasonal dimorphism " are afforded by many tropical butterflies which possess a darker " wet-season " and a brighter " dry-season " generation. So different in appearance are often these two seasonal forms that before their true relationship was worked out they had been naturally regarded as independent species. The darkening of wingpatterns in many species of Lepidoptera has been carefully studied in our own British fauna. Melanic or melanochroic varieties are specially characteristic of western and hilly regions, and some remarkable dark races (fig. 43) of certain geometrid moths have arisen and become perpetuated in the manufacturing districts of the north of England. The production of these melanic forms is explained by J. W. Tutt and others as largely due to the action of natural selection, the damp and sooty conditions of the districts where they occur rendering unusually dark the surfaces - such as rocks, tree-trunks and palings - on which moths habitually rest and so favouring the survival of dark, and the elimination of pale varieties, as the latter would be conspicuous to their enemies. Breeding experiments have shown that these melanic races are sometimes " dominant " to their parent-stock. An evidently adaptive connexion can be frequently traced between the resting situation and attitude of the insect and the colour and pattern of its wings. Moths that rest with the hindwings concealed beneath the forewings (fig. 34, f) often have the latter dull and mottled, while the former are sometimes highly coloured. Butterflies whose normal resting attitude is with the wings closed vertically over the back (fig. 63) so that the under surface is exposed to view, often have this under surface mottled and inconspicuous although the upper surface may be bright with flashing colours. Various degrees of such " protective resemblance " can be traced, culminating in the wonderful " imitation " of its surroundings shown by the tropical " leaf-butterflies " (Kallima), the under surfaces of whose wings, though varying greatly, yet form in every case a perfect representation of a leaf in some stage or other of decay, the butterfly at the same time disposing of the rest of its body so as to bear out the deception. How this is effected is best told by A. R. Wallace, who was the first to observe it, in his work The Malay Archipelago: " The habit of the species is always to rest on a twig and among dead or dried leaves, and in this position, with the wings closely pressed together, their outline is exactly that of a moderately sized leaf slightly curved or shrivelled. The tail of the hindwings forms a perfect stalk and touches the stick, while the insect is supported by the middle pair of legs, which are not noticed among the twigs and fibres that surround it. The head and antennae are drawn back between the wings so as to be quite concealed, and there is a little notch hollowed out at the very base of the wings, which allows the head to be retracted sufficiently." But the British Vanessids often rest on a bare patch of ground with the brightly coloured upper surface of their wings fully exposed to view, and even make themselves still more conspicuous by fanning their wings up and down. Some genera and families of Lepidoptera, believed to secrete noxious juices that render them distasteful, are adorned with the staring contrasts of colour usually regarded as " warning," while other genera, belonging to harmless families sought for as food by birds and lizards, are believed to obtain complete or partial immunity by their likeness to the conspicuous noxious groups. (See Mimicry.) Sexual dimorphism is frequent among the Lepidoptera. In many families this takes the form of more elaborate feelers in the male than in the female moth. Such complex feelers (fig. 2) bear numerous sensory (olfactory) nerve-endings and give to the males that possess them a wonderful power of discovering their mates. A single captive female of the Endromidae or Lasiocampidae often causes hundreds of males of her species to " assemble " around her prison, and this character is made use of by collectors who want to secure specimens. In many butterflies - notably the " blues " (Lycaenidae) - the male is brilliant while the female is dull, and in other groups (the Danainae for example) he is provided with scent-producing glands believed to be " alluring " in function. The apparent evidence given by the sexual differences among the Lepidoptera in favour of C. Darwin's theory of sexual selection finds no support from a study of their habits. The male indeed usually seeks the female, but she appears to exercise no choice in pairing. In some cases the female is attracted by the male, and here a modified form of sexual selection appears to be operative. The ghost swift moth (Hepialus humuli) affords a curious and interesting example of this condition, the female showing the usual brown and buff coloration of her genus, while the wings of the male are pure white, rendering him conspicuous in the dusky evening when pairing takes place. But in the northernmost After Ratzeburg, Insect Life, vol. 2 (U.S. Dept. Agr.).
FIG. 16. - Pupa of Gypsy Moth (Porthetria dis par) sheltered in leaves joined by silken threads. Below is the cast larval cuticle.
A B FIG. 17. - Vapourer Moth (Ocneria detrita). S. Europe. A, Male; B,'Female.
haunts of the species, where there is no midsummer night, the male closely resembles the female in wing patterns, the development of the conspicuous white being needless. A very interesting sexual dimorphism is seen in the wingless condition of several female moths - the winter moths (Hybernia and Cheimatobia) among the Geometridae and the vapourers (Orgyia and Ocneria) among the Lymantriidae for example (fig. 17). It might be thought that the loss of power of flight by the female would seriously restrict the range of the species. In such insects, however, the caterpillars are often active and travel far.
The range of the Lepidoptera is practically world-wide; they are absent from the most remote and inhospitable of the arctic and antarctic lands, but even Kerguelen possesses a few small indigenous moths. Many of the large and dominant families have a range wide as that of the order, and certain species that have attached themselves to man - like the meal moths and the clothes moths - have become almost cosmopolitan. Interesting and suggestive restrictions of range can, however, be often traced. Although butterflies have been found in 82° N. latitude in Greenland, they are unknown in Iceland, and only a few species of the group reach New Zealand. Three large sections - the Ithomiinae, Heliconiinae and Brassolinae - of the great butterfly family Nymphalidae are peculiar to the Neotropical region, while the Morphinae, a characteristically South American group, have a few Oriental genera in India and Indo-Malaya. The Acraeinae, another section of the same family, have the vast majority of their species in Ethiopian Africa, but are represented eastwards in the Oriental and Australian regions and westwards in South America. A comparison of the lepidopterous faunas of Ireland, Great Britain and the European continent is very instructive, and suggests strongly that, despite their power of flight the Lepidoptera are mostly dependent on land-connexions for the extension of their range. For example, Ireland has only forty of the seventy species of British butterflies. The range of many Lepidoptera is of course determined by the distribution of the plants on which their larvae feed.
Nevertheless certain species of powerful flight, and 'some that might be thought feeble on the wing, often cross sea-channels and establish or reinforce distant colonies. Caterpillars of the great death's head moth (Acherontia atropos) are found every summer feeding in British and Irish potato fields, but it is doubtful if any of the pupae resulting from them survive the winter in our climate. It is believed by Tutt that the species is only maintained by a fresh immigration of moths from the South each summer. Hosts of white butterflies (Pieris) have been frequently observed crossing the English Channel from France to Kent. Migrating swarms of Lepidoptera have often been met by sailors in mid-ocean; thus, Tutt records the presence around a sailing ship in the Atlantic of such a swarm of the rather feeble moth Deiopeia pulchella, nearly 1000 m. from its nearest known habitat. This migratory instinct is connected with the gregarious habits of many Lepidoptera. For example, H. W. Bates states that at one place in South America he noticed eighty different species flying about in enormous numbers in the sunshine, and these, with few exceptions, were males, the females remaining within the forest shades. Darwin describes a " butterfly shower," which he observed to m. off the South American coast, extending as far as the eye could reach; "even by the aid of the telescope," he adds, "it was not possible to see a space free from butterflies." Sir J. Emerson Tennent, witnessed in Ceylon a mighty host of butterflies of white or pale yellow hue, " apparently miles in breadth and of such prodigious extension as to occupy hours and even days uninterruptedly in their passage." Observations at Heligoland by H. Gatke have shown that migrating moths " travel under the same conditions as migrating birds, and for the most part in their company, in an east to west direction; they fly in swarms, the numbers of which defy all attempts at computation and can only be expressed by millions." The painted lady butterfly (Pyrameis cardui) comes in repeated swarms from the Mediterranean region into northern and western Europe, while in North America companies of the monarch (Anosia archippus) invade Canada every summer from the United States, and are believed to return southwards in autumn. This latter species has, during the last half-century, extended its range south-westwards across the Pacific and reached the Austro-Malayan islands, while several specimens have occurred in southern and western England, though it has not established itself on this side of the Atlantic. It is noteworthy that the introduction of its food-plant - Asclepias - into the Sandwich Islands in 1850 apparently enabled it to spread across the Pacific.
Our knowledge of the geological history of the Lepidoptera is but scanty. Certain Oolitic fossil insects from the lithographic stone of Solenhofen, Bavaria, have been described as moths, but it is only in Tertiary deposits that undoubted Lepidoptera occur, and these, all referable to existing families, are very scarce. Most of them come from the Oligocene beds of Florissant, Colorado, and have been described by S. H. Scudder. The paucity of Lepidoptera among the fossils is not surprising when we consider the delicacy of their structure, and though their past history cannot be traced back beyond early Cainozoic times, we can have little doubt from the geographical distribution of some of the families that the order originated with the other higher Endopterygota in the Mesozoic epoch.
The order Lepidoptera contains more than fifty families, the discussion of whose mutual relationships has given rise to much difference of opinion. The generally received distinction is between butterflies or Rhopalocera (Lepidoptera with clubbed feelers, whose habit is to fly by day) and moths or Heterocera (Lepidoptera with variously shaped feelers, mostly crepuscular or nocturnal in habit). This distinction is quite untenable as a zoological conception, for the relationship of butterflies to some moths is closer than that of many families of Heterocera to each other. Still more objectionable is the division of the order into Macrolepidoptera (including the butterflies and large moths) and the Microlepidoptera (comprising the smaller moths). Most of the recent suggestions for the division of the Lepidoptera into sub-orders depend upon some single character. Thus J. H. Comstock has proposed to separate the three lowest families, which have - like caddis-flies (Trichoptera) - a jugum on each forewing, as a sub-order Jugatae, distinct from all the rest of the Lepidoptera - the Frenatae, mostly possessing a frenulum on the hindwing. A. S. Packard places one family (Micropterygidae) with functional mandibles and a lacinia in the first maxilla alone in a sub-order Laciniata, all the rest of the order forming the sub-order Haustellata. T. A. Chapman divides the families with free or incompletely obtect and mobile pupae (Incompletae) from those with obtect pupae which never leave the cocoon (Obtectae), and this is probably the most natural primary division of the Lepidoptera that has as yet been suggested. Dyar puts forward a classification founded entirely on the structure of the larva, while Tutt divides the Lepidoptera into three great stirps characterized by the shape of the chorion of the egg. The primitive form of the egg is oval, globular, or flattened with the micropyle at one end; from this has apparently been derived the upright form of egg with the micropyle on top which characterizes the butterflies and the higher moths. These schemes, though helpful in pointing out important differences, are unnatural in that they lay stress on single, often adaptive, characters to the exclusion of others equally important. Although it is perhaps best to establish no division among the Lepidoptera between the order and the family, an attempt has been made in the classification adopted in this article to group the families into tribes or super-families which may indicate their probable affinities. The systematic work of G. F. Hampson, A. R. Grote and E. Meyrick has done much to place the classification of the Lepidoptera on a sound basis, so far as the characters of the imago are concerned, but attention must also be paid to the preparatory stages if a truly natural system is to be reached.
Jugatae. Three families are included in this group having in common certain primitive characters of the wings and neuration (see fig. 6), as well as of the larva and pupa. There is a membranous lobe or j ugum near the base of the wing, and the neuration of the hindwing is closely like that of the forewing, the radial nervure being fivebranched in both. The pupa has four or five movable segments, and the larval prolegs have complete circles of hooklets.
The three families of the Jugatae are not very closely related to each other. The Micropterygidae (often known as Eriocephalidae), comprising a few small moths with metallic wings, are the most primitive of all Lepidoptera. They are provided with functional mandibles, while the maxillae have distinct laciniae, well-developed palps and galeae not modified for suction (see fig. 3). The larva is remarkable on account of its long feelers, the presence of pairs of jointed prolegs on the first eight abdominal segments, an anal sucker beneath the last segment and bladder-like outgrowths on the cuticle. These curious larvae feed on wet moss. The family has only a few genera scattered widely over the earth's surface (Europe, America, Australia, New Zealand).
The Eriocraniidae resemble the Micropterygidae in appearance, but the imago has no mandibles, and the maxillae, though short and provided with conspicuous palps, have no laciniae and form a proboscis as in Lepidoptera generally. The abdomen of the female carries a serrate piercing process, and the eggs are laid in the leaves of deciduous trees, the white larvae, with aborted legs, mining in the leaf tissue. The fully-fed larva winters in an underground cocoon and then changes into the most remarkable of all known lepidopterous pupae, with relatively enormous toothed mandibles which bite a way out of the cocoon in preparation for the final change. These pupal mandibles of the Eriocraniidae, together with the nature of the imaginal maxillae in the Micropterygidae (Eriocephalidae) and the wing-neuration in both families, point strongly to a relationship between the Lepidoptera and the Trichoptera.
The Hepialidae or swift moths - the third family of the Jugataeare in some respects specialized. The moths are of large or moderate size with the maxillae in a vestigial condition, no food being taken after the attainment of the perfect state. The larvae (fig. 12) feed either on roots or in the wood of trees and shrubs, not attaining their growth in less than a year and some large exotic species living for two or three. The family is world-wide in range, and Australia possesses some almost gigantic and strangely coloured genera.
Tineides. A large assemblage of moths, mostly of small size, are included in this group. The wings have no jugum, but there is a frenulum on the hindwing, which has, as in all the groups above the Jugatae, only a single radial nervure. Three anal nervures are present in the hindwing in those families whose wings are well developed, but in several families of small moths the wings of both pairs are very narrow and pointed, and the neuration is consequently reduced. The sub-costal nervure of the hindwing is usually present and distinct from the radial nervure. The egg is flat except in the Cossidae and Castniidae in which it is upright. The larval prolegs, with few exceptions, have a complete circle of hooklets, and the larvae usually feed in some concealed situation. The pupa is incompletely obtect, with three (in some females only two) to five free abdominal segments, and emerges partly from the cocoon before the moth appears. The cremaster serves to anchor the pupa to its cocoon at the correct degree of emergence, and thus facilitates the eclosion of the imago.
The Cossidae are a small family of large moths (figs. 8, 18, 19) belonging to this section, characterized by their heads with erect rough scales or hairs, the pectinate feelers of the males, their reduced maxillae so that no food is taken in the perfect state, and their wings with the fifth radial nervure arising from the third, and the main median nervure forking in the discoidal areolet. The larvae feed in plant stems, often in the wood of trees, forming tunnels and galleries, and usually taking a year or more to reach maturity. The pupa which has three or four free segments in the male and four or five in the female, rests in a cocoon within the food plant, often strengthened by chips of wood, or in a subterranean cocoon. The family is fairly well represented in the tropics; the British fauna possesses only three species, of which the " goat " (Cossus cossus) and the " leopard " (Zeuzera pyrina) are well known, the caterpillars of both being often injurious to timber and fruit trees.
The Tortricidae are a large family of small moths (see fig. I), nearly allied to the Cossidae. The fifth radial nervure does not arise from the third, the maxillae are well developed, but their palps are obsolete; the head is densely clothed with erect scales; the terminal segment of the labial palp is short and obtuse. The female pupa has three, the male four, free segments. All the larvae of these moths have some method of concealing themselves while feeding. A frequent plan is to roll up a leaf of the food-plant, fastening the twisted portion with silken threads so as to make a tubular retreat; this is the habit of the caterpillar of the green bell moth (Tortrix viridana) which often ravages the foliage of oak plantations. The larvae of the pine-shoot moths (Retinia) shelter in solidified resinous exudations from their coniferous food-plants, while the codlin-moth caterpillar (Carpocapsa pomonella) feeds in apples and pears, growing with the growth of the fruit which affords them both provender and home. The antics of " jumping-beans " are due to the movements of tortricid caterpillars within the substance of the seed.
The Psychidae are a small but widely-distributed family of moths whose males have the head, densely clothed with rough hairs, bearing complex, bipectinated feelers, but with the maxillae reduced and useless. The larvae live in portable cases made of grass, pieces of leaf or stick, with a silken lining, and these cases serve as-cocoons for the pupae which agree in structure with those of the Tortricidae. But the most remarkable feature of the family is the extreme degradation of the female, which, wingless, legless and without jaws or feelers, never emerges from the cocoon.
The Castniidae are a small family of large, conspicuous, day-flying exotic moths (fig.
20) whose clubbed feelers and bright colours give them a resemblance to butterflies, although their wingneuration is of the primitive t in e o i d type; the smooth larvae feed on the stems or roots of plants and the pupal structure agrees with that of the Tortricidae and FIG. 20. - Castnia acraeoides. Brazil. Psychidae. The distribution of the family is confined to Tropical America and the Indo-Malayan and Australian regions.
The Zygaenidae (burnet moths) are a large family of day-flying moths (fig. 21) adorned with brilliant metallic colours. The feelers are long, stout in the middle and tapering, bearing numerous long or short pectinations. The well-developed maxillae have vestigial palps. The larvae - often very conspicuously coloured - are remarkable among the Tineides in having incomplete circles of hooks on the prolegs, and they feed exposed on the leaves of various plants. The pupa, enclosed in a silken cocoon, has four or five free segments. The Limacodidae are a small FIG. 2 I: Neuro- family of brownish nocturnal moths, allied to symploca concinna. the Zygaenidae and agreeing with them in the S. Africa. structure of the pupa. The larva in this family also is an exposed feeder, but it is remarkable in form, being flattened and slug-like, without prolegs and adorned with curious spinous processes.
The Sesiidae are a large family of small, narrow-winged moths, the sub-costal nervure of the hindwing being absent and the wings being for the most part destitute of scales (fig. 22). The maxillae are developed but their palps are vestigial, while the terminal segment of the labial palp is short and pointed. Many of these insects have their bodies banded with black and yellow; this in conjunction with the transparent wings makes some of them like wasps or hornets in appearance. The larvae feed in the woody stems of various A B plants. The pupa, with FIG. 22. - A, Sesia asiliformis (Gad-fly three or four free abHawk Moth). Europe. B, Larva. dominal segments, re mains within its cocoon, formed with chips of wood, until the time for its final change draws near; then it works itself partly out of the tree by means of the spines on its abdominal segments.
The Nepticulidae are the smallest of all the Lepidoptera, measuring only 3-8 mm. across the outspread wings, which are all lanceolate and pointed at the tip. The sucking portions of the maxillae are vestigial, but the palps are long and jointed. The larvae, without FIG. 1 8. - Stygia australis. S. Europe.
FIG. 19. - Zeuzera scalaris. India.
?----???, ? ...- /";% ?? A, 4@ 494 thoracic limbs or prolegs, but sometimes with paired rudimentary processes on some of the segments, mine in the leaves of plants. The pupa, with four free abdominal segments in the female and five in the male, rests in a cocoon usually outside the mine.
The Adelidae are a family of delicate, but larger, moths with very long feelers (fig. 23) especially in the males. The larvae feed, when young, in flowers, later, protected by a flat case, they devour leaves, the pupa resembles that of the Nepticulidae in structure. The female has an ovipositor adapted for piercing plant tissues.
The Tineidae are a large and important family of small moths (figs. 14, 24, 25) with rough-haired heads, and with the maxillae FIG. 23. - Adela FIG. 24. - Euplocampus FIG. 25. - Tinea degeerella. Europe. anthracinus. Europe. tapetzella (Clothes Moth). Europe.
and their palps usually well developed. Many of the genera have narrow pointed wings with degraded neuration. The larvae differ in their habits, some - Gracilaria for example - mine in leaves, while others, like the well-known caterpillars of the clothes moth (Tinea) surround themselves with portable cases (fig. 14) formed by spinning together their own excrement. The female pupa has three, the male four free abdominal segments.
Plutellides. This group includes a few large families of small moths that are linked by their imaginal and larval structure to the Tineidae (in which they have often been included) and by their pupal structure to the higher groups that have yet to be considered. The moths have labial palps with slender pointed terminal segments, and narrow pointed wings, but the neuration (except in the Elachistidae) is less degenerate than in most Tineidae. The hairy covering of the head is smooth, and the maxillary palps are usually vestigial. The egg is flat, and the larval prolegs have complete circles of hooklets. The pupa is obtect with only two free abdominal segments (fifth and sixth) in both sexes and does not move out of the cocoon.
Four families are included in this group. The Plutellidee (fig. 26) have the maxillary palps developed, in some genera, as slender threadlike appendages directed straight forward. The larvae do not usually mine in leaves, but feed openly, keeping to the underside for protection (Plutella), or spinning by their united labour a mass of web over the foodplant (Hyponomeuta). In the other three families the maxillary palps are vestigial or obsolete. The Elachistidae have remarkably narrow, pointed wings and their larvae mine in leaves or form portable cases and feed among seeds. In the Oecophoridae (fig. 27) the sub-costal nervure of the hindwing is free and distinct throughout its length, and the larvae usually feed among spun leaves or seeds, or in decayed wood. The Gelechiidae are a large family with similar larval habits; the moths are distinguished by the sinuate termen of the hindwing and the connexion of its sub-costal nervure with the discoidal areolet.
Pyralides. This group includes a number of moths of delicate build with elongate legs, the maxillae and their palps being usually well developed. The forewings have two anal nervures, the hindwings three (fig. 30, h, i); in the hindwing the subcostal nervure bends towards and often connects with the FIG. 28. - Ptero- FIG. 29. - Orneodes radial, and the phorus spilodactylus. hexadactylus (24-plumed f r e n u 1 u m i s Europe. Moth). Europe. usually present.
The egg is flat.
The larva has complete circles of hooklets on its five pairs of prolegs, and the pupa (usually completely obtect) does not move at all from its cocoon. This group includes the only Lepidoptera that have aquatic larvae.
Of the families comprised in this division three deserve special mention. The Pterophoridae (plume moths, fig. 28) usually have the wings deeply cleft - a single cleft in the forewing and two in the hindwing. The hairy larvae feed openly on leaves, while the soft and hairy pupa remains attached to its cocoon by the cremaster, although it is incompletely obtect and has three or four free abdominal segments. The Orneodidae (multiplume moths) have all the wings six-cleft. Our British species, Orneodes hexadactyla (fig. 29), is an exquisite little insect, whose larva feeds on the blossoms of honeysuckle. The pupa is completely obtect, with only two free abdominal segments. The Pyralidae (figs. 13, 30), a large family with numerous divisions, have entire wings, and their pupae are After Riley and Howard, Insect Life, vol. 2 (U.S. Dept. Agr.).
FIG. 30. - Flour Moth (Ephestia kiihniella). c, With wings spread. d, Head and front body-seg f At rest. [wings. ments of larva. g, h, i, Marking and neuration of e, 2nd and 3rd abdominal seg a, Larva. ments, more highly magni b, Pupa; twice natural size. fled.
obtect. The caterpillars feed in some kind of shelter, some spinning a loose case among the leaves of their food-plant, others burrowing into dry vegetable substances or eating the waxen cells of bees. Several species of this group, such as the Mediterranean flour moth, Ephestia kiihniella (fig. 30), become serious pests in storehouses and granaries, their larvae devouring flour and similar food-stuffs.
Noctuides. In this group may be included a number of families of moths with the second median nervure of the forewing arising close to the third. This feature of neuration characterizes also the Jugatae (see fig. 6), Tineides, Plutellides and Pyralides. But the Noctuides differ from these groups in having only two anal nervures in the hindwing. The maxillary palps are absent or vestigial, and a frenulum is usually present on the hindwing. The larva has usually ten prolegs, whose hooklets are arranged only along the inner edge, while the immobile pupa is always obtect with only two free abdominal segments (the fifth and sixth). The Lasiocampidae and their allies have flat eggs, but in the Noctuidae, Arctiidae and their allies the egg is upright.
The Lasiocampidae, together with a few small families, differ from the majority of this group in wanting a frenulum. The maxillae of the Lasiocampidae are so reduced that no food is taken in the imaginal state, and in correlation with this condition the feelers of the male are strongly (those of the female more feebly) bipectinated. The moths are stout, hairy insects, usually brown or yellow in the pattern of their wings. The caterpillars are densely hairy and many species hibernate in the larval stage. The pupa is enclosed in a hard, dense cocoon, whence the name " eggars " is often applied to the family, which has a wide distribution, but is absent from New Zealand. The Drepanulidae are an allied family, in which the frenulum is usually present, while the hindmost pair of larval prolegs are absent, their segment being prolonged into a pointed process which is raised up when the caterpillar is at rest. The hook-tip moths represent this family in the British fauna.
FIG. 26. - Cero- stoma asperella. Europe.
FIG. 27. - Psecadia pusiella.
The Lymantriidae resemble the Lasiocampidae in their hairy bodies and vestigial maxillae, but the frenulum is usually present on the hindwing and the feelers are bipectinate only in the males. Some females of this family - the vapourer moths (Orgyia and allies, fig. 17), for example - are degenerate creatures with vestigial wings. The larvae (fig. 15) are very hairy, and often carry dense tufts on some of their segments; hence the name of " tussocks " frequently applied to them. The pupae are also often hairy (fig. 16) - an FIG. 31. - Claterna cydonia. India.
exceptional condition - and are protected by a cocoon of silk mixed with some of the larval hairs, while the female sheds some hairs from her own abdomen to cover the eggs. The family is widely distributed, its headquarters being the eastern tropics. To that part of the world is restricted the allied family of the Hypsidae, FIG. 32. - Ophideres imperator. Madagascar.
distinguished from the " tussocks " by the slender upturned terminal segment of the labial palps and by the development of the maxillae. The Noctuidae are the largest and most dominant family of the Lepidoptera, comprising some Io,000 known species. They are mostly moths of dull coloration, flying at dusk or by night. The maxillae are well developed, the hindwing has a frenulum, and its sub - costal nervure touches the radial near the base. The larvae of the Noctuidae (fig. 34, c) are rarely hairy and the pupa (fig. 34, d) usually rests in an earthen cell, being often the wintering stage for the species; sometimes the pupa is enclosed in a loose cocoon of silk and leaves. In some Noctuidae (fig. 32) the hindwings are brightly coloured, but these are concealed beneath the dull, inconspicuous forewings when the insect rests (fig. 34, f). Nearly allied to the Noctuidae, but very different in appearance, are the gaily-coloured Agaristidae, a family of day-flying moths (figs. 35, 36), confined to the warmer regions of the globe and distinguished by From Mally, Bull. 24, Div. Ent. U.S. Dept. Agr. FIG. 34. - e, f, Heliothis armigera. Europe. c, Larva; d, pupa in cell. Natural size. a, b, Egg, highly magnified.
their thickened feelers, those of the Noctuids being thread-like or slightly pectinate.
The Arctiidae (tiger moths, footmen, &c.) are allied to the Noctuidae, but their wing-neuration is more specialized, the sub-costal nervure of the hindwing being confluent with the radial for the basal part of its course. These moths (fig. 37) have gaily coloured wings, and the caterpillars are often densely covered with long smooth hairs. The pupae are enclosed in silken cocoons (fig. 38). The highest specialization of structure in this group of the Lepidoptera is reached by the Syntomidae, a family nearly allied to the Arctiidae, but with the sub-costal nervure in the hindwing absent. The Syntomidae have elongate narrow forewings and short hindwings, usually dark in colour with clear spots and dashes destitute of FIG. 35. - Rothia pales. Madagascar.
scales (fig. 40). The body, on the other hand, is often brilliantly adorned. The family, abundant in the tropics of the Old World, has only two European species.
Sphingides. This group includes a series of families which agree with the Noctuides in most points, but are distinguished by the origin of the FIG. 36. - A egocera rectilinea. FIG. 37. - Haploa Lecontei. Tropical Africa. N. America.
second median nervure of the forewing close to the first, or from the discocellular nervure midway between the first and third medians (see fig. 5). These neurational characters may appear somewhat insignificant, but such slight though constant distinctions in structures of no adaptational value may be safely regarded as truly significant of relationship. Several of the families in this After Lugger, Riley and Howard, Insect Life, vol. a (U.S. Dept. Agr.).
FIG. 38. - c, Tiger Moth (Phragmatobia fuliginosa, Linn.). Europe. a, Caterpillar; b, cocoon with pupa. Slightly enlarged.
group have lost the frenulum. In larval and pupal characters the Sphingides generally resemble the Noctuides, but in some families there is a reduction in the number of the larval prolegs. The egg is spherical or flat, upright only in the Notodontidae.
The Notodontidae are stout, hairy moths (figs. 5, 41, 42 a) with maxillae and frenulum developed. In the larva the prolegs on the FIG. 39. - Halias prasinana. Europe. FIG. 40. - Euchromia formosa. S. Africa.
hindmost segment are sometimes modified into pointed outgrowths which are carried erect when the caterpillar moves about. From these structures whip-like, coloured processes are protruded by the caterpillar (fig. 42 b) of the puss moth (Cerura) when alarmed; these processes are believed to help in " terrifying " the caterpillar's enemies. Allied to the Notodontidae are the Cymatophoridae - a family of moths agreeing with the Noctuidae in appearance and habits - and the large and important family of the Geometridae. FIG. 33. - Cyligramma fluctuosa. W. Africa.
The moths (fig. 43) of this family are distinguished from the Notodontidae by their delicate build and elongate feet, the caterpillars (fig. 43, c) by the absence or vestigial condition of the three anterior pairs of prolegs. The two hinder pairs of prolegs are therefore alone FIG. 41. - Notodonta ziczac (Pebble Prominent Moth). Europe.
Gil FIG. 42b. - Larva of Cerura (Puss Moth).
functional and the larva progresses by " looping," i.e. bending the body so as to bring these prolegs close up to the thoracic legs, and then, taking a fresh grip on the twig whereon it walks, stretching the body straight out again. Many of these larvae have a striking After Grote, Natural Science (J. M. Dent & Co.).
FIG. 43. - Geometrid Moth (Amphidasys betularia, Linn.). Europe. a, Large grey type; b, dark variety; c, caterpillar in looping attitude.
resemblance both in form and colour to the twigs of their foodplant. In some of the species the female has the wings reduced to useless vestiges. The family is world-wide in its range. The tropical Uraniidae are large handsome moths (figs. 44, 45), often with ex FIG. 44. - Urania boisduvalii. Cuba.
quisite wing-patterns, allied to the Geometridae, but distinguished by the absence of a frenulum in the moth and the presence of the normal ten prolegs in the larva.
The Sphingidae (hawk moths) are insects often of large size (figs. 46a, 47), with spindle-shaped feelers, elongate and powerful forewings and the maxillae very well developed. The hindwing carries a frenulum and has its sub-costal nervure connected with the radial by a short bar. The caterpillars have the full number of prolegs, and, in many genera, carry a prominent dorsal horn on the eighth abdominal segment (fig. 46 b). The pupa lies in an earthen cell. On account of their powerful flight the moths of this family have a wide range; certain species - like Acheronlia atropos and Protoparce convolvuli - migrate numbers almost every summer.
FIG. 46a. - Chlaenogramma jasminearum (Jessamine Sphinx). N. America.
A group of families in which the first maxillae are vestigial, the feelers bipectinate and the pupa enclosed in a have been regarded as the most highly specialized of all the moths, though according to other views the whole series of the Lepidoptera culminates in the Syntomidae. Of these cocoonspinning families may be specially mentioned the Eupterotidae, large brown or yellow moths inhabiting tropical Asia and Africa, and represented in Europe only by the " processionary moth" (Cnethocampa processionea). In this family the frenulum is present, and the larvae are protected with tufts of long hair. The Bombycidae have no frenulum, and FIG. 47. - Smerinthus ocellatus (Eyed Hawk moth). Europe.
the larvae are smooth, with some of the segments humped and the eighth abdominal often carrying a dorsal spine. The family in Islands British into the dense silken cocoon, FIG. 42a. - Cerura borealis. N. America.
FIG. 45. - Urania boisduvalii at rest, showing under surface of wings.
its distribution, but the common silkworm (Bombyx has become acclimatized in southern Europe and is most of the silk used in manufacture and art. Of After C. V. Riley, Bull. rg, Div. Ent. U.S. Dept. Agr. FIG. 48. Bombyx mori. China. a, Caterpillar (the common silk-worm); b, cocoon; c, male moth.
commercial value also is the silk spun by the great moths of the family Saturniidae, well represented is warm countries and contributing a single species (Saturnia pavonia-minor) to the British fauna. These moths (fig. 49) have but a single anal nervure in the hindwing and only three radial nervures in the forewing. The wing-patterns are handsome and striking; usually an unsealed " eyespot " is conspicuous at the end of each discoidal areolet. The Grypocera. This group stands at the base of the series of families that are usually distinguished as " butterflies." The feelers are recurved at the tip, and thickened just before the extremity. The forewing has the full number of radial nervures, distinct and evenly spaced, and two anal nervures; the frenulum is usually absent. The larvae (fig. 51) have prolegs with complete circles of hooklets, and often feed in concealed situations, while the pupa is protected by a light cocoon. The affinities of this group are clearly not with the higher groups of moths just described, but with some of the lower families. According to Meyrick they are most closely related to the Pyralidae, but Hampson and most other students would derive them (through the Castniidae) from a primitive Tineoid stock allied to the Cossidae and Zygaenidae.
Three families are included in the section. The North American Megathymidae and the Australian Euschemonidae have a frenulum and are usually reckoned among the " moths." The Hesperiidae in which the frenulum is wanting form the large family of the skipper butterflies, represented in our own fauna by several species. They are insects with broad head - the feelers being widely separated - usually brown or grey wings (fig. 50) and a peculiar jerky flight. The family has an extensive range but is unknown in Greenland, New Zealand, and in many oceanic islands.
Rhopalocera. This group comprises the typical butterflies which are much more highly specialized than the Grypocera, and may be readily distinguished by the knobbed or clubbed feelers and by the absence of a frenulum. Two or more of the radial nervures in the forewing arise from a common stalk or are suppressed. The egg is " upright." The larvae have hooklets only on the inner edges of the prolegs. The pupa is very highly modified, only two free abdominal segments are ever recognizable, and in some genera even thesehave become consolidated. The cocoon is reduced to a pad of silk, to which the pupa is attached, suspended by the cremastral hooks; in some families there is also a silken girdle around the waist-region. In correlation with the exposed condition of the pupa, we find the presence of a specially developed FIG. 51. - Chrysalis and head-piece " or " nose-horn " to Larva of Ni s o n i a d e s t a g e s protect the head-region of the con- (dingy skipper). Europe. tamed imago. Their bright colours and conspicuous flight ,in the sunshine has made the Rhopalocera the most admired of all insects by the casual observer.
A modification that has taken place in several families of butterflies is the reduction of the first pair of legs. H. W. Bates arranged the families in a series depending on this character, but neurational and pupal features must be taken FIG.152. - Chrysophanus thoe. N. America.
into account as well, and - the sequence followed here is modified from that proposed by A. R. Grote and J. W. Tutt.
The Lycaenidae are a large family including the small butterflies (figs. 52, 53, 54) popularly known as blues, coppers and hairstreaks. The forelegs in the female are normal, but in the male the tarsal segments - are shortened and the claws sometimes are absent. The forewing has only three or four radial nervures (fig.55),the last two of which arise from a common stalk; the feelers are inserted close together on the head. The larva is short and hairy, somewhat like a woodlouse in shape, the broad sides concealing the legs and prolegs, while the pupa, which is also hairy or bristly, is attached by the cremaster to a silken pad and cinctured with a silken thread. The upper surfaces of the wings of these insects are usually of a bright metallic hue - blue _ or coppery - while beneath there are often FIG. 53. - Rathinda amor. India. FIG. 54. - Cheritra freja. India.
numerous dark centred " eye-spots." The family is widely distributed. Nearly related are the Lemoniidae, a family abundantly represented in the Neotropical Region, but scarce in the Old World and having only a single European species (Nemeobius lucinia) which occurs also in England. In the Lemoniidae (figs. 56, 57) the forelegs of the male are reduced and useless for walking. The Libytheidae may be recognized by the elongate snout-like palps, is tropical in mori, fig. 48) the source of FIG. 49. - Epiphora bouhiniae. W. Africa.
caterpillars are protected by remarkable spine-bearing tubercles (fig. 10, B).
FIG. 50. - Tagiades sabadius. S. Africa.
the five-branched radial nervur?. of the forewing, the cylindrical hairy larva, and the pupa attached only by the cremaster. The Papilionidae are large butterflies with ample wings, and all six legs fully developed in both sexes. The forewing has five radial and two anal nervures, the second of the latter being free from the first and running to the dorsum of the wing, while the hindwing has but a single anal, and is frequently prolonged into a " tail " at the FIG. 58. - Papilio machaon (Swallow-tail). Europe.
third median nervure (fig. 58). The larva is cylindrical, never hairy but often tuberculate and provided with a dorsal retractile tentacle (osmaterium) on the prothorax. The pupa, which has a ,, ,,`?
double " nose-horn," is attached by the cremaster and a waistgirdle to the food-plant in the Papilioninae (fig. 58), but lies in a web on the ground among the Parnasiinae (figs. 59, 60). The latter subfamily includes the well-known Apollo butterflies of the Alps.
The former is represented in the British fauna by the East Anglian swallow-tail (Papilio machaon), and is very abundant in the warmer regions of the world, in cluding some of the most magnificent and brilliant of insects.
Agreeing with the Papilionidae in the six perfect legs of both sexes and the cincture-support of the pupa we find the Pieridae - the family of the white and yellow butterflies (figs. 61, 62) - represented by ten species in the British fauna and very widely spread over the earth's surface. In the Pieridae there are two anal nervures in the hindwing, while the second anal nervure in the forewing runs into the first; the larva is cylindrical and hairy without an osmaterium. The pupa has a single " nose-horn," and in the more highly organized genera there is no mobility whatever between its abdominal segments. The wintering pupae of the common cabbage butterflies (Pieris brassicae and P. rapae) are common objects attached to walls and fences and their colour harmonizes, to a great extent, with that of their surroundings.
The Nymphalidae are by far the largest and most dominant family of butterflies. In both sexes the forelegs are useless for walking (fig. 63), the tarsal segments being absent and the short shins clothed with long hairs, whence the name of brush-footed butterflies is often applied to the family. The neuration of the wings resembles FIG. 62. - A ppias nero (male). Malaya that found among the Pieridae, but in the Nymphalidae the pupa, which has a double nose-horn (fig. 65) - as in Papilio - is suspended from the cremaster only, no girdling thread being present, or it lies simply on the ground. The egg is elongate and sub-conical in form FIG. 64. - Larva of Argynnis paphia (Silver-washed Fritillary). Europe.
and ornamented with numerous ribs, while the larva is usually protected by numerous spines (fig. 64) arising from the segmental tubercles. To this family belong our common gaily-coloured butterflies - the tortoiseshells, peacock (fig. 65), admirals, fritillaries 7 After Grote, Natural Science, vol. 12 (J. M. Dent & Co.).
FIG. 55. - Neuration of Wings in Lycaena. 2, Sub-costal.
7, 8, Anal nervures.
FIG. 56. - Eurybia carolina. Brazil FIG. 57. - Calephelis caenius. N. America.
FIG. 63. - Dione moneta. Brazil.
60. - Thais medesicaste.
FIG. 61. - Colias hyale (Pale clouded Yellow Butterfly). Europe.
and emperors. In most cases the bright colouring is confined to the upper surface of the wings, the under-side being mottled and often inconspicuous. Most members of the group Vanessidi - the peacock and tortoiseshells (Vanessa) and the red admiral (Pyrameis) for FIG. 65. - Vanessa io (Peacock) and its pupa.
hibernate in the imaginal state. This large family is divided into several sub-families whose characters may be briefly given, as they are considered to be distinct families by many entomologists. The Danainae (or Euploeinae, fig. 66) have the anal nervures of the forewing arising from a common stalk, the discoidal areolets in both wings closed, and the front feet of the female thickened; their FIG. 66. - Euploea leucostictos (male). Malaya.
larvae are smooth with fleshy processes. The danaine butterflies range over all the warmer parts of the world, becoming most numerous in the eastern tropics, where flourish the handsome purple Euploeae whose males often have " brands " on the wings; these insects are conspicuously marked and are believed to be distasteful to birds and lizards. So are the South American Ithomiinae, distinguished from the Danainae by the slender feet of the females; the narrow winged, tawny Acraeinae, with simple anal nervures, thick hairy palps and spiny larvae; and the Heliconiinae whose palps are compressed, scaly at the sides and hairy in front. This a last named sub-family is confined to the Neotropical Region, while the Acraeinae are most numerous in the Ethiopian. The Nymphalinae include the British 5 vanessids (fig. 65), and a vast 6 assemblage of exotic genera (figs. 68, 70), characterized by the " open " discoidal areolets (fig. 67) owing to the absence of the transverse " disco-cellular " nervules. In the Morphinae - including some magnificent South American insects with deep or azure FIG. 70. - Callithea sapphira. Brazil.
blue wings, and a few rather. dull-coloured l, Oriental genera - the areolets are closed in the forewings and often in the hind wings. The larvae of the Morphinae (fig. 71) are smooth 7 After A. R. Grote, Natural Science, vol. 12 (J. M. Dent & Co.).
FIG. 67. - Neuration of Wings in a Nymphaline Butterfly.
6, 7, 8, Anal nervures.
FIG. 68. - Nymphalis jason. W. Africa. Upper and under surface.
FIG. 69. - Larva and Pupa of Apatura ilia. or hairy with a curiously forked tail-segment. A similar larva characterizes the South American Brassolinae or owl-butterflies - FIG. 71. - Larva of Amathusia phidippus. FIG. 72. - Opsiphanes syme. Brazil.
FIG. 73. - Brassolis astyra. Brazil.
After A. R. Grote, Natural Science, vol.
iz (J. M. Dent & Co.).
FIG. 74. - Neuration of wings in Pararge, a satyrid butterfly.
7, 8, Anal nervures. FIG. 76 - Bia actorion. Brazil.
robust insects (figs. 72, 73) with the areolets closed in both wings, which are adorned with large " eye-spots " beneath. The Satyrinae, including our native browns and the Alpine Erebiae, resemble the foregoing group in many respects of structure, but the sub-costal nervure is greatly thickened at the base (fig. 74). This sub-family is world-wide in its distribution. One genus (Oeneis, fig. 75) is found in high northern latitudes, but reappears in South America. The dark, spotted species of Erebia are familiar insects to travellers among the Alps; yet butterflies nearly related to these Alpine insects occur in Patagonia, in South Africa and in New Zealand. Such facts of distribution clearly show that though the Nymphalidae have attained a high degree of specialization among the Lepidoptera, some of their genera have a history which goes back to a time when the distribution of land and water on the earth's surface must have been very different from what it is to-day.
Bibliography. - The handsome Lepidoptera, with their interesting and easily observed life-histories, have naturally attracted many students, and the literature of the order is enormous. M. Malpighi's treatise on the anatomy of the silkworm (De Bombycibus, London, 1669) and P. Lyonnet's memoir on the Goat-caterpillar, are among the earliest and most famous of entomological writings. W. F. Kirby's Handbook to the Order Lepidoptera (5 vols., London, 1894-1897) should be consulted for references to the older systematic writers such as Linnaeus, J. C. Fabricius, J. Hubner, P. Cramer, E. Doubleday and W. C. Hewitson. Kirby's Catalogues are also invaluable for the systematist. For the jaws of the Lepidoptera see F. Darwin, Quart. Journ. Mic. Sci. xv. (1875); E. Burgess, Amer. Nat. xiv. (1880); A. Walter, Jen. Zeits. f. Naturw. xviii. (1885); W. Breitenbach, Ib. xv. (1882); V. L. Kellogg, Amer. Nat. xxix. (1895). The last-named deals also with wing structure, which is further described by A. Spuler, Zeits. wiss. Zool. liii. (1892) and Zool. Jahrb. Anat. viii. (1895); A. R. Grote, Mitt. aus dem RoemerMuseum (Hildesheim, 1896-1897); G. Enderlein, Zool. Jahrb. Anat. xvi. (1903), and many others. For scales see A. G. Mayer, Bull. Mus. Comp. Zool. Harvard, xxix. (1896). For internal anatomy W. H. Jackson, Trans. Linn. Soc. Zool. (2) v. (1891), and W. Petersen, Mem. Acad. Imp. Sci. St Petersburg (8) ix. (1900). The early stages and transformations of Lepidoptera are described by J. Gonin, Bull. Soc. Vaud. Sci. Nat. xxx. (1894); E. B. Poulton, Trans. Linn. Soc. Zool. (2) v. (1891); H. G. Dyar, Ann. New York Acad. Sci. viii. (1894); T. A. Chapman, Trans. Entom. Soc. Lond. (1893), &c. For habits and life-relations see A. Seitz, Zool. Jahrb. Syst. v., vii. (1890, 1894); A. Weismann, Studies in the Theory of Descent (London, 1882) and Entomologist, xxix. (1896); F. Merrifield, Trans. Entom. Soc. Lond. (1890, 1893, 1905); M. Standfuss, Handbuch der paldarktischen Gross-schmetterlinge (Jena, 1896); R. Trimen, Proc. Ent. Soc. Lond. (1898); E. B. Poulton, Colours of Animals (London, 1890); Trans. Entom. Soc. (1892 and 1903), and Journ. Linn. Soc. Zool. xxvi. (1898); F. E. Beddard, Animal Coloration (London, 1892). For distribution see H. J. Elwes, Proc. Entom. Soc. Lond. (1894); J. W. Tutt, Migration and Dispersal of Insects (London, 1902); Fossil Lepidoptera, S. H. Scudder, 8th Rep. U.S. Geol. Survey (1889). Among recent general works on the Lepidoptera, most of which contain numerous references to the older literature, may be mentioned A. S. Packard's unfinished work on the Bombycine Moths of N. America, Mem. Nat. Acad. Sci. Philadelphia, vii. (1895), and Mem. Acad. Sci. Washington, lx. (1905); D. Sharp's chapter in Cambridge Nat. Hist. vi. (London, 1898); G. F. Hampson, Moths of India (4 vols., London, 1892-1896), and Catalogue of the Lepidoptera Phalaenae (1895) and onwards; S. H. Scudder, Butterflies of New England (3 vols., Cambridge, Mass., 1888-1889); W. J. Holland, Butterfly Book (New York, 1899). Works on the British Lepidoptera are numerous, for example, those of H. T. Stainton (1851), C. G. Barrett (1893-1907), E. Meyrick (1895), and J. W. Tutt (1899 and onwards). For recent general systematic works, the student should consult the catalogues mentioned above and the Zoological Record. The writings of O. Staudinger, E. Schatz, C. Oberthiir, K. Jordan, C. Aurivillius and P. Mabille may be specially mentioned.
(G. H. C.)
Subordines: Zeugloptera - Aglossata - Heterobathmiina - Glossata
Lepidoptera Linnaeus, 1758
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|Moths and butterflies|
The order Lepidoptera is the second biggest order in the class Insecta. It includes the butterflies, moths and skippers. Members of the order are called lepidopterans. A person who collects or studies this order is called a Lepidopterist. This order has more than 180,000 species in 128 families and 47 superfamilies. The order Coleoptera (the beetles) is the only order that has more species. The name, Lepidoptera, comes from the Ancient Greek words (scale) and (wing).
Lepidopterans go through complete metamorphosis. This means that they have a four parts of their life. The first part is the egg. The second part is the caterpillar or larva. The third part is the pupa. The last part is the adult or imago.
The larvae have a tough head and a soft body. They have mouths that are made to chew. Some larvae are covered with hairs, or other body extensions. The larvae have three pairs of small legs on the thorax. These legs are called true legs. There are up to five pairs of bigger legs on the abdomen. These legs are called prolegs. Lepidopteran larvae can be confused with the larvae of sawflies. The difference between Lepidopteran larvae and sawfly larvae is that Lepidopteran larvae have tiny hooks on their prolegs. These hooks are called crochets. Most larvae are herbivores, but a few are carnivores and detritivores.
Adults have two pairs of wings. They are covered by small scales. In some species, the adults have very small wings or no wings at all. This is more common in females. Adults have antennae. Some moths have antennae that look like feathers. These feather-like antennae are larger in males than females. Adults have a mouth part called a proboscis. It is made for nectar from flowers. Some adults do not have mouths and cannot feed. Others have different mouths that are made to pierce and suck blood or fruit juices.
A Skipper (Small skipper)
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