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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 is then withdrawn, the egg being lifted on to the back 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 p. 



The female has now become shrivelled, and 

 characteristic bright yellow spots appear under the 

 skin due to accumulation of uric acid in the malpighian 

 tubesand 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 



