430 
Biology of Ixodidae 
The part played by D. venustus in pathology is referred to on p. 426; 
see also Hadwen {Parasitology, vi. 283-297) and Hadwen and Nuttall 
{Ibid. 298-301) in connection with tick paralysis. 
HAEMAPHYSALIS CINNABARINA. 
This tick {H. chordeilis of American authors) requires three hosts 
upon which to feed as a larva, nymph and adult. The first to raise 
the tick were Hooker, Bishopp and Wood (1912, p. 98), who state that 
the larvae feed 5-12 days on rabbits or guinea-pigs; they twice failed 
to feed on fowls. Metamorphosis from larva to nymph takes 14 days 
at ca. 26° C. or 76 days at 12° C. Some unfed nymphs lived up to 
55-75 days. Nymphs, placed on cattle, fed for 5-8 days, and then 
underwent metamorphosis to adults in 26 days at 20° C. or in 186 days 
at ca. 15° C. (average temperature). Adults survived unfed for 100-305 
days. A female (probably unfertilized) remained for 19 days upon an 
ox; she then dropped off replete and survived for 172 days, but did 
not oviposit. 
The following observations were made by me in Cambridge with 
the progeny of 2 $ (N. 2452) taken from cattle in Winnipeg, Canada, 
and for which I am indebted to Mr J. R. N. Harrison. The ticks were 
raised on rabbits in experimental cages at room temperature (about 
15° C.) in the laboratory; they were kept in an incubator at 30° C. 
during metamorphosis. 
The recently emerged larvae were placed on a rabbit,on 27. xi. 1913: 
No. of gorged larvae 
collected ou 
successive days 
7 
on day 
5 
270 
>> 
6 
560 
99 
7 
306 
9f 
8 
160 
99 
9 
98 
9t 
10 
61 
99 
11 
15 
99 
12 
12 
99 
13 
The first nymphs emerged on 11. xii. 1913, i.e. metamorphosis from 
larva to nymph lasted 10-11 days at 30° C, On 6. i. 1914 the nymphs 
(100) were placed on a rabbit. 
