HEMIPTERA. 129 



PEDICULID.E. 



The division Pediculina, represented by the fam- 

 ily PedicuUdae, is regarded by Packard and Com- 

 stock as a subdivision equivalent to the sub-order of 

 Heteroptera or Homoptera. These insects are repre- 

 sented by the parasitic hce, occurring on the bodies 

 of mammals, including man. Fig. 77 is the human 

 louse {^Pediculus capitis, DeGeer), in- 

 habiting the head. In these insects 

 there are two simple eyes. The tho- 

 racic sutures have become indistinct, 

 although, according to Uhler, they can 

 always be made out by means of stain- 

 ing-fluids. This being the case, these 

 insects cannot be compared with sim- 

 ple adull forms like Campodea, Lepis- 

 ma, and the like, or with larval forms 

 Hke the larval locust, for in these the 

 thoracic sutures are distinct. They are probably in- 

 sects allied to the bed-bugs, that have become special- 

 ized by reduction resulting from parasitic habits. They 

 have lost not only their distinct thoracic sutures, but 

 also their faceted eyes and their wings, while the feet 

 have taken on characters adapting them for clinging 

 rather than leaping or running. 



The human-body louse (yPedicuhis vestivienti) has 

 several varieties, which agree in coloration with the 

 different races they live upon. The one which infests 

 the Caucasian race is yellowish, tinged with gray ; that 

 of the West African and Australian is nearly black ; 



