94 
Biology of Pediculus humanus 
The Distribution of Capitis on Man’s Body. 
As a rule capitis occurs on the head, mostly about the occiput and 
about the ears (see Plate III, and its legend). A number of authors 
state that it only occurs upon the head, but this is incorrect. Pinkus 
(1915, p. 239) writes that it is “strictly limited’’ to the head, but con¬ 
tradicts himself in the same paper by mentioning that it occasionally 
occurs on the body hair, extending to that of the pubis; he adds, 
however, that it does not proliferate there and that it has no significance 
in this situation. Several authors record the presence of capitis on 
the body. Denny (1842, pp. 14, 17) states that it doubtless prefers 
the head, yet it will stray over every part of the body, and he cites 
an observation of his own made at Leeds (see mention thereof on p. 96). 
Piaget (1880, p. 622) writes that it occasionally occurs on any part of 
the body and has consequently been at times confused with corporis. 
Brauer (1915, p. 561) finds that capitis not unrarely occurs on the body. 
Heymann (18. vm. 19l5, p. 304) states that in heavy infestations it 
spreads all over the body and clothing, according to an observation 
communicated to him by Wodermann. Lydston (cited by Brumpt, 
1910, p. 550, no reference) records its occurrence on the pubis. I 
describe a case of pure pubic infestation (see p. 86) wherein capitis 
proliferated actively in this situation. 
We may conclude that capitis usually occurs upon the head, that 
it may spread over the body, establishing itself on other hairy parts, 
and that it may be confined to the pubic hair and proliferate there as 
my case demonstrates. 
Modes of Infestation and Dissemination of Pediculus. 
In considering the modes of infestation, it is well to bear in mind 
the power possessed by lice of clinging to hair and cloth. This clinging 
power constitutes an essential factor in their dissemination. If pediculi, 
especially when hungry and agile, are placed in a glass, dish, they 
promptly cling to a piece of cloth or camels’ hair brush, or to a single 
human hair that is brought in their vicinity; in fact this is the quickest 
way of collecting them out of the dish. Numberless capitis, under these 
circumstances, will cling in line upon a single hair, and they are not 
readily removed by forceps, for, if the grip of a leg upon the hair is 
loosened, another leg or two at once grasps the hair. If head-lice, 
thus attached to a hair, are dropped into 70 % alcohol, the insects will 
all die in situ ; they appear to excel corporis in point of tenacity. 
