428 
Biology of Ixodidae 
The time required by D. venustus for metamorphosis. 
Egg to Larva. 
Larvae 
Eggs 
Eggs laid on 
emerged after 
maintained at 
20. xn. 1912 
38 days 
22° C. 
21. vn. 1913 
16 
30° C. 
1 
r Record by S. Hadwen, 
the unfed 
23. IV. 
7 
ca. 32° C. 1 
1 $s were taken 
from 
sheep at 
26. IV. 
10 
ca. 32° C. 
1 Chopaka, Brit. 
Columbia, and 
t transferred to a 
lamb. 
Larva to Nymph. 
Host 
Guinea-pig 
>» 
99 
99 
Nymph to Adults. 
Guinea-pig 
Ram 
Date when gorged 
tick dropped off 
host 
Nymphs 
emerged 
after 
Ticks maintained 
throughout at 
29. vn. 1912 
10 days 
24° C. 
9. vm. 
11 
99 
10. rv. 1913 
7 
30° C. 
29. IX. 
6 
99 
Adult emerged after 
18. IX. 1912 
14 days 
24° C. 
8. VI. 1913 
15 
ca. 30° C. 
Observations relating to oviposition in D. venustus. 
Obs. 
No. 
Host 
Date when 
gorged S 
dropped 
from host 
Oviposition 
began after 
Oviposition 
lasted 
Days $ 
survived 
after 
ovipos. 
ceased 
No. of 
eggs laid 
per ? 
Temperature at 
which $ 
was maintained 
1 
Ram 
9. xn. 1912 
11 days 
33 days 
14 days 
— 
24° C. 
2 
99 
18. vn. 1913 
3 
18 
14 
7140 
30° C. 
3 
Lamb 
19. IV. 
4 
— 
— 
— 
ca. 32° C. 
4 
99 
22. IV. 
4 
— 
—• 
— 
99 
5 
Jackal 
2. vin. 
5 
10 
1 
— 
30° C. 
6 
Dog 
25. vn. 
4 
22 
11 
3574 
99 
Note :—Observations 3 and 4 were made by S.Hadwen in British Columbia. In observa¬ 
tion 5 the 5 abandoned the jackal in a semi-gorged condition, there being no ^ upon 
the host; all the eggs failed to hatch. In observation 6 the $ was partly gorged 
when removed from the dog in which it produced tick paralysis (see Hadwen and 
NuttaU, Parasitology, vi. 298); it was also placed upon the host in the absence of 
a $ and laid eggs which were sterile. 
Longevity of unfed D. venustus. 
Larvae, which emerged 27. i. 1913, were active after 67 days, when they fed upon a 
guinea-pig; they were subsequently raised to adults. Adults, which emerged 2. x. 
1912, survived for 350 days when they attached themselves to a host. 
