180 NOCTURNA, OR MOTHS. HEPIALID^E ; BOMBYCID^E. 



Many of them have no distinct trunk ; and in some species the 

 females are almost, or altogether, without wings. Sometimes 

 the wings can be rolled round the body ; and in a few instances 

 they fold longitudinally, like a fan. The greater part of these 

 Lepidoptera fly by night, and their colours are usually dull. 

 Their Caterpillars vary as to the number of their legs, from ten 

 to sixteen ; their pupae are of rounded form, and almost always 

 spin a cocoon. The large number of species belonging to this 

 section, and the general similarity of their form, make their 

 classification a matter of some difficulty. They have been 

 divided into ten families ; of which it will be sufficient here to 

 notice the most important. 



709. The first family, that of HEPIALID.E, contains two 

 interesting genera, Hepialus and Cossus. The Moths of the 

 former are commonly termed Swifts, from the rapidity of their 

 flight, which takes place during the twilight ; the sexes vary 

 considerably in appearance and structure, the male of one 

 species, which frequents the Hop, being pure white, whilst the 

 female is yellow, with darker markings. The male is commonly 

 known as the Ghost-Moth, from his colour, and from his habit 

 of hovering with a pendulum-like motion, over one spot (often 

 in churchyards), where the female is concealed. The genus 

 Cossus contains the Goat-Moth, one of the largest of British 

 Lepidoptera ; which has received its common name from the 

 goat-like character of the strong scent emitted by the larva. 

 This larva feeds upon the wood of willow-trees, which it per- 

 forates in every direction, and thus so greatly weakens the trees, 

 that they are often blown down with the first strong wind. It 

 was this larva, which was so laboriously dissected by Lyonnet 

 ( 702) ; and his researches were continued upon the pupa and 

 imago, so as to constitute the most elaborate and complete 

 account of the anatomy of any Insect, that has been yet given to 

 the world. 



710. The family of BOMBYCID^ consists of Moths allied to 

 that of the common Silk-worm. The pupae are inclosed in 

 cocoons of pure silk, frequently of very firm texture ; and they 

 are rarely subterranean. The prevailing hues of these Moths 



