Page:EB1911 - Volume 16.djvu/494

Rh 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 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 resemblance both in form and colour to the twigs of their food-plant. 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 exquisite 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. 46b). 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 Acherontia atropos and Protoparce convolvuli—migrate into the British Islands in numbers almost every summer.

A group of families in which the first maxillae are vestigial, the feelers bipectinate and the pupa enclosed in a dense silken cocoon, 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 cocoon-spinning 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 the larvae are smooth, with some of the segments humped and the eighth abdominal often carrying a dorsal spine. The family 