F. C. Bishopp and H. P. Wood 
169 
In the Northern States where hatching does not take place until late 
summer or early fall, this resting period must be relatively shorter, at 
least for some individuals, as they begin infesting hosts in the late fall. 
This clustering habit is evidently of great value in protecting the larvae 
from the drying effects of the hot summer weather and the inactivity 
preserves their vitality. As previously stated, the larvae do not readily 
attach themselves to hosts when applied during their resting period in 
hot weather, and few of those which do attach themselves become en¬ 
gorged. 
TABLE IV. 
Moulting of larvae 
of Dermacentor albipictus 
when detached from host (ox). 
Date engorged 
larvae detached 
Dates of moulting 
Moulting 
period 
(days) 
No. 
moulted 
No. 
first moulted last moulteci 
1909 
1909 
Oct. 11 
2 
Oct. 23 
— 
12 
1 
» 14 
2 
„ 20 
— 
6 
1 
„ 15 
1 
„ 26 
— 
11 
1 
„ 16 
1 
„ 27 
— 
11 
1 
>, 20 
2 
„ 27 
Nov. 11 
7-22 
2 
,, 30 
1 
Nov. 27 
— 
28 
1 
1910 
1910 
Nov. 22 
2 
Jan. 11 
June 15 
50-54 
2 
» 23 
2 
24 ’ 
— 
62 
i 
„ 25 
2 
„ 11 
— 
47 
2 
1909 
Nov. 26 
3 
Dec. 7 
Jan. 26 
11-61 
3 
» 27 
13 
„ 1 
Feb. 20 
10-82 
11 
>, 29 
9 
„ 7 
8 
8-71 
6 
„ 30 
7 
,, 7 
„ 15 
7-77 
6 
Dec. 2 
3 
„ 31 
Jan. 20 
29-49 
3 
1910 
1910 
Jan. 27 
3 
Mar. 7 
Mar. 9 
39-41 
2 
„ 29 
1 
„ 4 
— 
34 
1 
Feb. 25 
2 
„ 22 
— 
25 
1 
Mar. 1 
1 
„ 22 
— 
21 
1 
Totals 57 46 
The longevity of the larvae of this species has been found to range 
from 60 to at least 346 days. Large masses of larvae left undisturbed 
on fairly moist sand showed the maximum longevity. 
When applied to a host some of the larvae attach themselves im¬ 
mediately while others fall off and may not secure an attachment for 
several days. The larvae are elongate oval in form and slate coloured 
Parasitology vi 12 
