422 
Biolofjy of Ixofllflae 
the larvae on a horse failed. When placed on a rabbit, the larvae 
gorged in 2-3 days, having attached themselves to the host’s 
eyehds and ears. A few dozen larvae placed on the rabbit brought 
about its death, although nothing more than an anaemic condition 
of the animal was observable at autopsy; 30 nymphs produced 
a similar effect when they were fed upon a second rabbit^. From 
5 gorged nymphs, taken from the second rabbit, there emerged 
5 adults (3 d, 2 $) after 17-18 days; three of these adults (1 S, 2 $) 
produced piroplasmosis in a horse upon which they were placed 
15-16 days after their emergence from the nymphal skin. The 
horse showed P. caballi in its blood and a temperature of 40° C. 
on the 12th day after the tick infestation took place. Some unfed 
larvae survived for 6 months.] 
The time D. reticulatus remains upon the host. 
Larvae. 
Remarks 
Larvae placed on host 
24 days after emergence. 
Nymphs placed on host 
14 days after emergence. 
Hadwen and NuttaU (1913) Parasitology, vi. 299-301, observed deaths in guinea- 
pigs to which larvae and nymphs of Dermacentor venustus were applied. Aragao (1912, 
pp. 96 et seq.) also noted fatal effects following the infestation of toads and snakes with 
Amblyomma agamum. In the absence of any parasites in the blood in any of these cases 
the deaths may, provisionally, be attributed to toxic secretions emanating from the ticks. 
Host 
Ram 
Date when 
ticks were put 
on liost 
8. vn. 1913 
Host maintained 
at average 
temp, of 
19° C. 
No. of gorged 
ticks collected on 
successive days 
164 on day 3 
450 „ 4 
111 „ 5 
29 „ 0 
Nymphs. 
Ram .30. vii. 1913 
19° C. 
754 
65 
90 
84 
13 
.f; 
6 
7 
8 
9 
10 
Adults (9). 
247 
Ram 
20. V. 1913 
19° C. 
1 on day 
9 
Ram 
30. IX. 
14° C. 
1 » 
13 
Ram 
14. X. 
9° C. 
2 „ 
8 
1 
1 
2 
12 
13 
15 
89 
