G. H. F. Nuttall 
450 
Stimmary. 
Rhipicephalus sanguineus requires three hosts upon which to feed 
in the larval, nymphal and adult stages. The tick was readily reared 
by us under experimental conditions, the larvae being raised on dogs 
and rabbits, the nymphs on dogs, jackal and hedgehog, the adults on 
dogs and jackal. Under favourable conditions the larvae and nymphs 
are ready to feed 3-7 days after emergence, the adults in about a week. 
The length of time the ticks feed upon the host (dog or jackal) is 3-8 
days (mostly 4 days) for the larva, 3-11 days (mostly 4 days) for the 
nymph. The character of the host appears to exert an influence, for 
we found that nymphs feed longer upon the hedgehog (10-17 days) 
than they did upon the other hosts mentioned. Females fed for 7-21 
days (mostly 8 days); the d persists upon the host for an undetermined 
period. The temperature at which the host is maintained appears to 
exert no influence upon the duration of the parasitic period of the 
immature stages, in the case of larvae the recorded temperatures ranged 
from 6-5° to 20° C., with nymjrhs it ranged from 8° to 18° C.; our 
observations on $s are too few to warrant any conclusions in this respect, 
but at 1-5° to 5° C., most of them abandoned the host on the 8th day 
which is about what has been observed to take place in a warm climate 
(India). Copulation takes place upon the host. The ds readily detach 
themselves and are often found wandering about, this behaviour, 
coupled with the fact that the $s are somewhat more numerous, permits 
of the conclusion that a d may copulate with several $s. Proportion 
of the sexes: of 707 adults, descended from 2 ?s, 285 were d and 422 
were $. The time required for metamorphosis from egg to larva is 
17-19 days at 30° C., 75 days at 12° C.; from larva to nymph 5-8 days 
at 30° C.; from nymph to adult 11-12 days at 30° C. are required. 
The loss of life during metamorphosis is slight under favourable con¬ 
ditions, thus only 3 out of 58 larvae failed, after engorgement, to emerge 
as nymphs, and in one of two experiments only 4 out of 579 nymphs 
failed, after engorgement, to attain maturity. Oviposition commenced 
3-6 days (mostly 3-4 days) after the $ had abandoned the host when the 
ticks were maintained at 30° C.; oviposition only began on the 25th 
day at 12° C.; the process lasted 9-15 days and the ?s survived 1-19 
days after the process was completed, having laid 1400 to 3900 eggs 
at 30° C. Longevity of some unfed ticks was very marked: one out 
of 20 lots of larvae survived for 253 days; on the other hand only 
2 out of 55 nymphs survived for 97 days; adults in one case showed 
