G. H. F. Nuttall 
121 
was viewed in ventral aspect during the act of oviposition. I subse¬ 
quently observed the act on two occasions. The posterior abdominal 
lobes were seen to be retracted and protruded several times during the 
process and to approach and separate from each other in the median 
line as if feeling and then grasping the hair. The appearance of the 
pointed end of the egg was preceded by a flow of cement and the egg 
was rapidly extruded. The females quickly released the hair from the 
grip of the gonopods after the egg issued, and they walked away from 
it. A third female made repeated and violent efforts to void an egg 
but failed to do so; between the throes she remained hanging to the 
hair by the gonopods whilst she rested. 
In this connection I may mention that a hair can be readily passed 
either from in front or behind through the circular space between the 
gonopods in dead and living females; the manipulation recalls that 
of passing a thread through the eye of a needle. I threaded the insects 
under a low magnifying power; my Laboratory Assistant succeeded 
in doing so with the naked eye (i) after I had shown him the manipula¬ 
tion on specimens long preserved in alcohol. Insects thus treated 
remained hanging to the hair by their gonopods. When at rest, the 
pincers- formed by the gonopods being closed, the circular interspace 
coincides with the calibre of ordinary fine human hair; where the hair 
is broader or two adjoining hairs have to be grasped the gonopods 
readily adapt themselves by becoming more or less separated (see 
Fig. 4 A). That the gonopods aid in fixing the eggs on fabrics is 
evident from the position of the eggs on the fibres; in an alcohol 
specimen I once found fibres between the gonopods, these having 
emanated from the felt on which the female had laid. 
The Orientation and Mode of Attachment of the Egg. 
Whilst the egg is in the ovary, its operculum is directed toward 
the head of the female, and it maintains this orientation when it 
issues from the sexual orifice. 
The position of the female when she oviposits is the factor determin¬ 
ing the orientation of the egg when it is laid ; thus, when she lays an egg 
on a hair, say on the scalp, she usually walks away from the scalp, and 
the operculum is consequently directed toward the distal end of the 
hair, the egg being cemented near the hair root. On moderately 
infested heads as a rule only one nit per hair is found, but a con¬ 
siderable number of eggs may be laid one behind the other upon a 
