340 
Pediculus and Phthirus 
are invalid for reasons of priority (= corporis as defined by me). The names 
maculatus, angustus, and marginatus applied by Fahrenholz to supposed 
varieties of capitis and corporis (themselves but races, or varieties if liberally 
interpreted!), cannot be recognized, for they are surely based on faulty 
observation. 
The specific names applied to lice (other than Pedicinidae) found on 
monkeys and apes, i.e. consobrinus Piaget 1880, affinis Mjoberg 1910, 
schdffi Fahrenholz 1910, lobatus and oblongus Fahrenholz 1913, mjobergi 
Ferris 1916 (= affinis Mjoberg, v. supra), apply either to invalid or to very 
doubtful species and are attributed here to P. humanus race capitis which 
have established themselves on these animals during confinement, having 
been in contact with man. Until these purported species have been adequately 
differentiated from those occurring on man, they certainly cannot be accepted 
as valid. There is nothing strange about it that man’s lice should occasionally 
establish themselves on other Primates than man. (Note that Noeller (1916) is 
stated to have raised P. humanus on the pig. See also my two records showing 
that Phthirus may parasitize the dog!) 
2. The relationship between capitis and corporis. 
In considering the relationship existing between these two forms which 
some have regarded as species and others not, it is necessary to dwell upon the 
supposed differences which have been considered sufficient to separate the 
forms specifically. 
(a) Morphological differences. 
Morphological differences between typical examples of capitis and corporis 
were already indicated by Guerin-Meneville (1829-44, PI. II) by illustrations 
showing capitis with palps short and broad, abdomen having angular segments 
and deep intersegmental indentations laterally 1 , pigmentation dark. In corporis 
on the other hand, the palps appear longer and slenderer, the abdominal 
segments are rounded with shallower intersegmental indentations, whilst 
pigmentation is absent. These differences have been pointed out by many 
subsequent writers, some indeed appear to have believed that they discovered 
them. 
Size. Stress has been laid upon the smaller size of capitis. It has been 
asserted that the largest capitis is always smaller than the smallest corporis, 
even by such recent authors as Fahrenholz (1912) and Cummings (1915). 
That capitis may however exceed corporis in size has been pointed out by 
Neumann (1910), Popoff (1916) and Sikora (ix. 1917) whose statements I 
can confirm. Whilst capitis is usually smaller than corporis, there is no 
difficulty—given a sufficient number of specimens—in obtaining a series 
wherein in point of size the one form merges into the other. 
Details of structure. According to various recent authors, capitis (compared 
1 Especially in adults. 
