G. H. F. Nuttall 
391 
anatomical structure would indicate, is more prone to be disseminated 
passively than is Pediculus. 
The fact that Phthirus in most cases remains confined to the pubic 
region already proves that it does not tend to wander actively. This 
tendency to remain localized upon a limited area of the host’s skin is 
well exemplified in the graphic records (Figs. 7 and 8) relating to a 
couple of insects raised by me experimentally, neither of them in the 
course of their active lives wandering beyond the borders of a rectangle 
of skin measuring 16 x 10 cm. 
II. METHOD OF RAISING PHTHIRUS EXPERIMENTALLY. 
Having failed to find any evidence in the literature that crab-lice 
have hitherto been raised experimentally, I append a brief description 
of the method that was employed by me successfully. 
Hairs bearing single nits were removed from an infested soldier, 
and the nits were examined microscopically to see that they were 
suitable for experiment. After trying to let them hatch upon the leg 
by tying the nit-bearing hairs to leg-hairs, it was found more satisfactory 
to allow the eggs to hatch in a tube carried next to the skin in the 
inguinal region, the young larvae, as they emerged, being transferred 
to the base of a hair on the leg by means of a camel hair brush. The 
latter procedure was preferred because the nits were found to slip off 
the cut hairs when the first method was employed and the larvae often 
became entangled in the stocking and died without having fed. On the 
other hand, when the lice were carefully placed near the base of a hair 
so that their heads were directed toward the skin, the young larvae 
transferred from the tube, at once proceeded to feed and gave no further 
trouble. As newly emerged unfed larvae were found to die or grow feeble 
in a few hours after emergence, the tube in which the eggs hatched was 
therefore subjected to frequent inspection so that the larvae should be 
placed on the leg as soon as possible after hatching out. 
The larvae, having been allowed to anchor themselves, the leg was 
covered by a closely woven black cotton stocking that was held in 
position by two garters placed above and below the knee. The exact 
spot where each insect anchored was charted by means of fixed points 
marked on the skin, a pair of compasses being used to register the spots 
on a daily record sheet. In this way the development and movements 
of each insect could be followed, the leg (my Laboratory Assistant’s) 
being examined one or more times a day as occasion required, a hand 
Parasitology x 26 
