FIG. 17.-STRUCTURE OF PUPA, LARVA AND ADULT OF MEDITERRANEAN FLOUR MOTH (EPHESTIA KUHNIELLA) by their larvae having abdominal feet usually only present on the 6th and loth segments, and they consequently progress in a series of loops (hence the name geometers or loopers). They are mostly thin-bodied moths of slender build with relatively large wings, and structurally they are separable from other Noto dontoidea by Sc being strongly bent and separate from R, for a short distance at the base of the fore wing. The Notodontidae, or prominents, have vein Sc-I-Ri running close to or joining the cell, and are stout hairy moths, whose larvae sometimes have the anal claspers modified into slender processes, well exhibited in the puss moth (Dicranura vinula) (fig. 24). The Sphingidae, or hawk moths, are swiftly flying, powerful insects with narrow wings, and the antennae are thickened, but taper to a point which is generally hooked ; in the hind wings is connected with the cell by a bar. Familiar examples are the death's head moths (Acherontia) and the widely-spread convolvulus hawk moth (Proto parce convolvuli).
Fore wings with vein M, usually joining Hind wings with Sc+R, diverging from cell at the base and remote from Rs; frenulum present or absent ; haustellum present. This small tropical group comprises only two families. The most important are the Uraniidae, which include large moths gen erally with tailed wings and the costal region of the hind wings moths or to the Castniidae. They are divided into three sub families which are sometimes regarded as of family rank. The Hesperiinae, or true skippers, are a very large group, occurring in most parts of the world, while the giant skippers or Mega thymiinae belong to the tropics of America, and the Euschemo ninae are Australian. It is noteworthy that the male of Euschemon is the only butterfly possessing a frenulum and at one time this genus was placed among moths of the family Castniidae.
In the remainder of the butterflies certain of the veins of the fore wings are coincident and do not arise separately from the cell.
greatly expanded and no frenulum. They are often day-flying insects, closely resembling butterflies in general appearance, and are among the most exquisitely coloured of all Lepidoptera (fig.
25).
Differ from the Uranoidea in having R5 joined to R4; haustellum absent.
These insects are essentially tropical with but few representa tives in temperate lands ; the antennae are strongly pectinated, especially so in the males, and the haustellum and frenulum are generally absent. The Bombycidae include the well-known silk worm moth (Bombyx mori) (fig. 26) and have two anal veins to the hind wings. The Saturniidae, or emperor moths (fig. 27), have a single anal vein to the hind wings and comprise some of the largest of all Lepidoptera, the atlas moths of the Orient having a wing-expanse up to ten inches. Their larvae construct dense silken cocoons, and in some species the silk is used commercially.
Antennae clubbed or swollen at their apices and a frenulum wanting.
The Papilionoidea, or butterflies, can be readily separated from the moths, or remainder of the Lepidoptera, by the above-men tioned characters and it is noteworthy that clubbed antennae are also found in certain moths, but in such cases the frenulum is present. The most primitive family of butterflies are the Hes periidae, or "skippers," which have all the veins in the fore wings arising separately from the cell. They derive their popular name from their erratic darting flight which is different from the more sustained movements of other butterflies. Their affinities are by no means clear, but they are probably related either to Pyralid The Papilionidae or swallow-tails are large insects, mainly trop ical ; the majority have tails to the hind wings and they are among the most magnificent of all insects. The fore legs are fully devel oped in both sexes and the hind wings have only a single anal vein. The larvae are smooth or provided with fleshy tubercles, and there is a dorsal retractile scent organ or osmeterium on the prothorax; the pupae are attached head upwards, by means of a girdle of silk and a cremaster. The genus Papilio is world-wide and the species P. machaon (fig. 28) is the sole English member of the family. The Apollo butterflies (Parnassius) are alpine, with translucent wings, and their pupae are exceptional in being enclosed in a loose web among leaves.