G. H. F. Nuttall 
311 
Boophilus decoloratus lays 120()-4o00 eggs. 
Ixodes ricinus „ 2400-3200 
Rhipicephalus hursa „ 4900-6900 „ 
R/tipicephalus sanguineus „ ca 2000-3000 , 
Haemaphysalis leachi „ 2400-4800 „ 
The rate of metamorphosis varies considerably according to the 
temperature at which the ticks are maintained. In Boophilus, the life- 
cycle is rapidly completed because the tick is incubated upon the warm 
blooded host throughout its parasitic period, and it does not lose time in 
having to find a host after each ecdysis. In Boophilus, the cycle from 
egg to egg may last 120 days, in R. hursa it lasts somewhat longer, in 
/. ricinus it lasts 178 days, these being minimum periods observed 
under experimental conditions. 
Behaviour of Piroplasma in Ticks. 
When a fertilized female tick has fed upon an infected animal the 
parasites she imbibes undergo development within her body. About 
the fourth or fifth day after the parasites have entered the tick’s gut, 
there appear free club-shaped bodies which move about with vermiform 
movements and are encountered in the gonads. Their further develop¬ 
ment is obscure, but in infective ticks both Christophers (Fig. 8) and 
Marzinowsky state that they have found minute bodies, which may 
provisionally be called Sporozoites, in the salivary glands. 
In Boophilus and Ixodes the larvae, descended from infected parents, 
ai-e infective. In H. leachi the larvae and nymphs are not infective ; 
the ticks, descended from an infected parent, only infect the host when 
they have attained maturity (Lounsbury, Nuttall). In R. sanguineus the 
larvae are not infective, but the nymphs and adults are; when nymphs 
are fed on an infected host the adult tick is infective (Christophers). 
With R. bursa (two-host tick) the larvae are not infective, but the adults 
are (Motas). I have found adults of H. leachi infective after starving for 
seven months, and believe that ticks harbouring Piroplasma remain 
infective as long as they live. 
Unfed ticks may withstand prolonged starvation. I have seen unfed 
larvae of I. ricinus still lively after 176 days starvation; B. annulatus 
larvae were lively after 251 days starvation; B. bursa adults were lively 
after 343 days starvation. In this connection, I only mention the 
longevity of stages which may transmit piroplasmosis. It is clear that 
three-host ticks are the most difficult to eradicate by treating infested 
