448 
Biology of Ixodidae 
the process lasts 24-48 days (usually 31-48 days) and the female survives 
1-44 days after oviposition has ceased. Counts of the number of eggs 
laid per female showed a range of roundly 4960-6900. Longevity: 
larvae were successfully raised after starving for 182 days, others, out 
of 24 lots observed, survived up to 363 days; the longevity of nymphs 
was not recorded; some adults survived up to 640 days, in one case, 
after 279 days’ fasting, roundly a fourth of the males and a third of the 
females were found to have died out of a lot of 3363 adults. As both 
sexes in the lot were almost equally represented, this indicates that the 
males are perhaps longer-lived than the females. Adults after fasting 
323 days and over have fed on a ram and are now yielding eggs (4th 
generation). Judging from our protocols the life-cycle under favourable 
conditions could scarcely be completed in less than about 110 days. 
The part played by R. hursa in the transmission of ovine piroplas- 
mosis is referred to on p. 439. 
RHIPICEPHALUS SANGUINEUS. 
The ticks to which the following protocols relate, were derived from 
two sources: {a) N. 237, were received 29. viii. 1906, from Cairo, Egypt, 
through the courtesy of Professor Heinrich Bitter; the consignment 
comprised unfed adults and eggs from which larvae subsequently 
emerged, (b) N. 1932, adults, received 27. x. 1912, fi’om the Central 
Research Institute, Kasauli, Prmjab, India, the ticks having been 
forwarded by Captain C. D. Mackay to Major Christophers, I.M.S., 
whilst the latter was working in the Quick Laboratory. 
[The only information we possess regarding the biology of this 
tick is cootained in the publications of Christophers (1907 a, p. 4; 
1907 h, pp. 40-43) and Patton and Cragg (1913, p. 642). Whilst 
the information supplied is meagre, it establishes certain essential 
points in the life-history. I shall quote the papers by Christophers 
by the numbers ^ and the work of Patton and Cragg by the 
number ^ in the follovdng two paragraphs so as not to overload 
the text with references which would interfere with their perusal. 
The details these authors give are cited in extenso, but I have 
arranged the data in accordance with the order adopted throughout 
this paper. The writers mentioned, are, also for brevity’s sake, 
cited as “Authors” in the column headed “Remarks” in my 
protocols. As far as can be gathered the Authors used only dogs 
for the observations they record below, though they state that the 
jackal is a suitable host; they do not mention the temperature at 
