ANNULOSA: INSECTA. 



345 



certain how they may most naturally be distributed amongst 

 the higher orders. 



SUB-CLASS I. AMETABOLA. Young not passing through a 

 metamorphosis ) and differing from the adult in size only. Imago 

 destitute of wings ; eyes simple, sometimes wanting. 



ORDER I. ANOPLURA. Minute Aptera,' in which the mouth 

 is formed for suction ; and there are two simple eyes. 



This order comprises insects which are commonly parasitic 

 upon man and other animals, and are known as Lice (Pedi- 

 culi). The common Louse (fig. 180, A) is furnished with a 



Fig. 180. Morphology of Aptera. A, Pedicidus hutnanns capitis ', B, Docopkorus 

 hamatus, one of the Bird-lice ; C, Campodea, ; D, Degeeria, one of the Poduridce ; 

 E, Scale of a Podurid, as seen under the microscope ; F, Degeeria purpurascens. 

 All the figures are greatly enlarged. (After Packard and Gervais.) 



simple eye, or ocellus, on each side of a distinctly differen- 

 tiated head, the under surface of which bears a suctorial 

 mouth. There is little distinction between the thorax and 

 abdomen, but the segments of the former carry three pairs 

 of legs. The legs are short, with short claws or with two 

 opposing hooks, affording a very firm hold. The body is 

 flattened and nearly transparent, distinctly segmented, and 

 showing the stigmata very plainly. The young pass through 



