METAZOA INSECTA. 465 



invisible. This covering or pupa-case is really formed of 

 the hairs thrown off by the caterpillar and these are fast- 

 ened together by silk. 



There are scarcely any Lepidopterous insects that are 

 parasites, but Epipyrops anomala Westw., is an exception, 

 since its caterpillar (PI. 1181, fig. i, cast skin of a young 

 larva; fig. 2 fully grown larva, dorsal view; fig. 3, ventral 

 view) is found attached to the back of the Chinese lan- 

 tern fly, Hotinus candelarius Linn. 



The body is flattened and broadened out while the 

 legs are greatly reduced in size. When young the larvae 

 are free from the wax secreted by the Hotinus, but as 

 they develop they become entirely covered with it. 



According to Westwood these parasites probably feed 

 upon the waxy secretions of the Hotinus. When full 

 grown they drop off their host and secrete "a cottony 

 substance " doubtless made from their waxy food, which 

 serves as a cocoon (fig. 4) for the pupa (fig. 5). After a 

 variable time (from nine days to upwards of twelve 

 months) the moth (fig. 6) escapes. 



Since Epipyrops is an external parasite it has not 

 undergone marked structural changes but its life history 

 is unique among Lepidoptera. 



The green larvae of the hawk moths or Sphingidae 

 have the habit of raising the forward end of the body 

 and holding it motionless for a long time ; hence the 

 name of the family. They feed on the tomato, potato, 

 and tobacco plants. The common species is Phlegethon- 

 tius celeus ( = Macrosila quinquemaculata Haw.) (No. 

 1182, larva, pupa, and moth). The pupa is not pro- 

 tected by a cocoon, but is a chrysalis with a long han- 

 dle-like appendage which is the case of the sucking tube. 



The adult (No. 1182) is a swifter flier than most Lepi- 

 doptera, and this habit is correlated with the structure of 

 the mesothorax and metathorax, these two segments being 

 more closely consolidated in the hawk moths than in other 

 members of the order. 



