406 LEPIDOPTERA 



CHAP. 



some species the walls of the cocoons have a firm appear- 

 ance, looking veiy like egg-shell a fact which is supposed to 

 have given rise to the name of Eggers. Professors Poultoii 

 and Meldola have informed us that this appearance is produced 

 by spreading calcium oxalate on a slight framework of silk, 

 the substance in question being a product of the Malpighian 

 tubes. 1 In various families of Lepidoptera it happens that 

 occasionally the pupa exists longer than usual before the appear- 

 ance of the perfect Insect, and in certain members of this family 

 notoriously in Poecilocampa populi, the December moth this 

 interval may be prolonged for several years. There is not at 

 present any explanation of this fact. It may be of interest to 

 mention the following case : From a batch of about 100 eggs 

 deposited by one moth, in the year 1891 (the Puss-Moth of the 

 family Notodontidae), some sixty or seventy cocoons were obtained, 

 the feeding up of all the larvae having been effected within 

 fourteen days of one another ; fourteen of the Insects emerged 

 as moths in 1892 ; about the same number in 1893 ; in 1894, 

 twenty-five; and in 1895, eleven emerged. Lasiocampidae is a 

 large family, consisting of some 100 genera and 500 or more 

 species, and is widely distributed. It is unfortunately styled 

 Bombycidae by some naturalists. 



Fam. 30. Endromidae. The "Kentish glory," Endromis 

 versicolor, forms this family ; it is a large and strong moth, and 

 flies wildly in the daytime in birch-woods. The larva has but 

 few hairs, and is said when young to assume a peculiar position, 

 similar to that of saw-fly larvae, by bending the head and thorax 

 backwards over the rest of the body. 



Fam. 31. Pterothysanidae. Consists of the curious East 

 Indian genus Pterothysanus, in which the inner margins of the 

 hind wings are fringed with long hairs. They are moths of 

 slender build, with large wing-expanse, black and white in colour, 

 like Geometrids. There is no frenulum. Metamorphoses un- 

 known. 



Fam. 32. Lymantriidae. (Better known as LiparidaeX 

 These are mostly small or moderate-sized moths, without brilliant 

 colours ; white, black, grey and brown being predominant : with 

 highly-developed, pectinated antennae in the male. The larva 

 is very hairy, and usually bears tufts or brushes of shorter hairs, 



1 P. cut. Soc. London, 1891, p. xv. 



