ANOPLURA : BIONOMICS 553 



(Polyplax) from rodents travel so rapidly among the hairs of the host that 

 it is often extremely difficult to catch them with forceps. The antennae 

 are moved from side to side in a very characteristic manner during pro- 

 gression. As shown in the above tables, they will feed twice a day,- 

 though one feed is enough to support them in the climate of Madras. 

 When fed artificially in this manner they always take a full meal, the 

 ingestion of blood being accompanied, as in so many blood-sucking insects, 

 by the evacuation of the contents of the hind gut ; the material first 

 passed out consists of small black particles, followed later by apparently 

 unaltered blood.* Adult vestimenti usually remain clinging to the cloth 

 on which they are kept throughout the meal, and show no disposition to 

 move away, but the larvae tend to wander actively about, in order, as 

 Warburton remarks, to establish themselves in new positions. 



The method of feeding can be easily observed through a lens without 

 disturbing the insect, though the parts are so small and so well concealed 

 that the details cannot be made out. The louse depresses the head 

 till it is in contact with the skin, and elevates the hind end of the body. 

 In a few seconds the pharynx appears as a bright red pulsating spot, 

 showing through the transparent integument of the head ; when a full 

 meal has been taken the abdomen becomes visibly distended, so much so 

 that young and transparent larvae look like small pink spots. The 

 irritation produced by the bite is very considerable in persons who are 

 not habitually subjected to it. 



Copulation can often be observed in vestimenti in captivity. It occurs, 

 according to Warburton, four or five days after the lice have reached the 

 adult stage. The method by which it is carried out is peculiar, and 

 resembles the habit of fleas. The female louse remains clinging to her 

 hold in the ordinary position, while the male, who is the smaller of the 

 pair, crawls underneath her, his back in contact with the ventral 

 surface of the female, and clasps her second pair of legs with his first 

 pair. The end of the abdomen is then tilted up and the penis inserted. 

 The two remain in this position for a considerable time. Copulation 

 takes place several times in the life of the female, as one might expect 

 from the fact that there is no receptacle for the sperms such as is found 

 in the Diptera and fleas. 



The outstanding fact in the bionomics of the body louse and this 

 applies also to lice from the monkey, pig, and buffalo is that it is extra- 

 ordinarily susceptible to even slight changes in its environment, and 



* Nicolle, Blaizot and Conseil state that spirochaetes are never passed out in the faeces of . 

 infected lice. 



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