head. The membrane is distended and bathed with 
the secretion from the cephalic gland. The ovipositor 
now places an egg on the edge of this membrane, which 
is then withdrawn, the egg being lifted on to the back 
of the head ; the tick moves slightly backward and 
a pile of eggs is thus deposited in front. 
The average size of an egg is 300 to 400 ^. 
The female has now become shrivelled, and 
characteristic bright yellow spots appear under the 
skin due to accumulation of uric acid in the malpighian 
tubes and much of this material (white) is passed per 
rectum. Egg laying takes several days ; the tick then 
dies. The eggs hatch in some weeks or months, and 
there emerges the 
Larva .—These are hexapod (Fig. 94). They 
cling to blades of grass, etc., and it may be several 
months before they have the chance of reaching a host. 
Observe the alimentary sac with lateral and posterior 
series of diverticula and the rhythmical contractions 
in these. In the gorged larva note under the micro¬ 
scope the diverticula swollen with blood and the large 
polygonal cells standing out clearly against the crimson 
contents. After feeding they go through a dormant pupa¬ 
like stage. This whole period lasts from a few days to 
several weeks. The first moult then takes place, either 
on the host or after leaving the host, on the ground. 
In this respect differences occur in different genera 
and species. Then emerges the 
Nymph .—These are octopod (Fig. 94). They 
resemble adult females, but have no sexual opening. 
This stage lasts from a few days to several weeks, the 
nymph becomes engorged with blood and, after the 
dormant stage, the second moulting takes place, either 
on the host, or after leaving the host, on the ground. 
Then emerges the 
