118 
Biology of Pediculus humanus 
96 hours had elapsed, the temperature having risen from ca. 15° C. 
to 22—23° C. in the last 48 hours; they then laid 8 eggs. 
A careful survey of the literature on lice has only revealed a single 
reference bearing directly upon the manner in which the louse oviposits, 
but it throws no light on the process. Widmann (vm. 1915, p. 292) 
states of the cement with which the female fastens her eggs, that it 
has the property of drying quickly, for he saw a freshly laid nit adhere 
to ■'the leg of a louse that climbed over a female as she was ovipositing 
and it was found impossible to remove it from the leg without injuring 
the limb. I have once seen a male to whose leg an egg was similarly 
cemented, and doubtless this arose in a like manner. 
Before describing the act of oviposition in P. humanus, I would 
refer the reader to Parasitology, ix. p. 312, wherein the copulatory 
organs of the female are described and figured. 
When viewing some living lice upon a hair-frame, of which a descrip¬ 
tion follows, it struck me that the “gonopods” might well serve as 
graspers for the hair upon which the female is desirous of ovipositing 1 . 
On reflection, it appeared certain that for the female to lay an egg 
in proper alignment upon a single hair, she must in some way hold 
her abdomen accurately in a line with the hair. Not only is the hair 
exceedingly pliable but the abdomen of the female louse is very pen¬ 
dulous especially when weighted with eggs and a full meal of blood. 
It is well that this hypothesis of the possible function of the gonopods 
was formed before the act of oviposition was observed, because the 
function of these organs might otherwise have been overlooked. The 
function of the outwardly directed chitinous spines lining the vagina 
and of certain muscles in connection with oviposition, has already been 
indicated (loc. cit. p. 316). 
The Process of Oviposition. 
To observe the act of oviposition, I constructed small frames of 
bent glass or copper wire, winding a knotted line of long hairs about 
them in the manner depicted in Fig. 6 C (p. 123). The hair was held in 
place by occasional knots and gum arabic lightly applied on the outer 
margin of the frame. The frames were then placed in cells of suitable 
size and shape to fit the frames (Fig. 6 A), being constructed in a simple 
manner out of glass plates held together by strips of gummed paper. 
1 In vol. ix. p. 301, I stated that the so-called gonopods took no part in the act of 
copulation as Peacock (1916, p 39) has assumed. 
