208 
Biology of Pediculus humanus 
Many authors, in seeking for differences between head-lice and body-lice, 
lay stress upon the colour. The head-louse is stated to have a dark or cindery 
gray colour, whilst the body-louse is light or pale coloured (Guerin, 1829-44; 
Cummings, 1915, etc.) but Schjodte (1864), Piaget (1880), Neumann (1910) 
and Sikora (1915) reject the colour difference as inconstant. Sikora (1917, 
p. 172), without giving the reference, cites Fahrenholz as lately having de¬ 
scribed Pediculus capitis var. maculatus from negroes, P. capitis var. angustus 
from Japanese, and P. corporis var. marginatus from Japanese, but makes no 
comments. Judging from Fahrenholz’s other publications to which I shall 
refer elsewhere, this author has also in this instance merely burdened science 
with three useless names which will fall into the synonymy of Pediculus 
humanus. 
Personal Observations. 
A survey of some thousands of lice that have reached me from various 
parts of the world, has revealed that they possess different degrees of pig¬ 
mentation which can be classified as follows; in the darkest specimens the 
markings (pleurae, bands, plates, etc.) appear blackish brown and the general 
integument dusky: 
Capitis. 
Very dark : N. 257, from Masai negro, German East Africa; N. 76, from 
negro, Obuasi, Ashanti; N. 244, from East Indian, Madras; N. 240, from Hill 
woman, Kasauli, India; N. 260, 263, East Indian, British Guiana; N. 231, 
from Arab, Khartoum, Sudan; N. 249, from native Indian, Lima, Peru. 
Very dark to dark (mostly very dark): N. 254, from Suaheli, Zanzibar; 
N. 243, from East Indian, Madras; N. 229, from Tamils, Federated Malay 
States. 
Dark : N. 235, from Badaga tribe, Nilgiris, India; N. 214, from Arabs, 
Algeria; N. 268, from Blackfoot Indians, Alberta, Canada; N. 146, from 
Chinese, Tientsin, China; N. 40, from Eskimo, Frobisher Bay, Baffinland. 
Medium : N. 246, from Copper Eskimo, Coronation Gulf Region; N. 176, 
from Chinese, Szechuen, China; N. 226, from native children, Salonika and 
Seres. 
Medium to pale : N. 208, 282, from grey-haired women (hair partly black 
or brown), lice mostly medium; N. 211, from soldier’s pubic hair (brown), lice 
mostly medium; N. 181, 209, from children, mostly medium. All of these lice 
were taken from Europeans. 
Corporis. 
Dark'. N. 225, from negroes and their clothes, Kibondo, Belgian Congo. 
Pale to very dark (mostly pale): N. 216, from negroes’ clothes, Nigeria; 
N. 277-281, from negroes, Nairobi, British East Africa. 
Pale to dark (mostly pale): N. 217, from Negroes’ blankets, Nyasaland; 
N. 269, from Blackfoot Indians, Alberta, Canada; N. 165, from Chinese, 
Szechuen, China; N, 213, from Arabs, Algeria. From Americans’ and Euro- 
