346 



THE INSECTS 



It is almost twice the size of the P. capitis and the abdominal seg- 

 ment is broader than the thorax. The abdomen is less markedly 

 festooned than that of P. capitis; is less hairy and contains 8 segments 

 as against 7 for P. capitis. 



It has recently been shown to transmit typhus fever and more recently Nicolle 

 has demonstrated it as a carrier of relapsing fever, the spirochaetes being introduced 

 by the material from the crushed louse being rubbed into the wound by the scratch- 

 ing of the victim (just as with the flea in plague) and not by the bite itself. The 

 dog louse as well as the dog flea serves as an intermediary host for Dipylidium. 



FIG. 82. Siphunculata and Rhynchota. i. Pediculus capitis. 2, Pediculus 

 vestimenti. 2 a. Protruded rostrum of Pediculus. 3. Phthirius pubis. 4. Acanthia 

 lectularia. 5. A. rotundata. 6. Conorhinus megistus. 



Phthirius pubis. This louse is popularly known as the crab louse. The female is 

 little more than % 5 inch in length, and the male a trifle less. They are almost 

 square. The second and third pair of legs are supplied with formidable hooks. 

 They have a preference for the white race and live about the pubic region. The 

 female lays about a dozen eggs, which hatch out in about a week. 



RHYNCHOTA 



The Rhynchota are insects possessing a sucking beak in which the 

 lower lip forms a long thin tube or rostrum which can be bent under the 



