184 
Biolorjy of Dermacentor 
when applied on December 11, 1911. On December 18 it was fully 
engoi’ged but became detached during an examination made on 
December 19. The nymphs, as well as the larvae, are easily loosened 
from the host, especially during the quiescent period prior to moulting. 
TABLE IX. Moulting of nymphs of Dermacentor nigrolineatus 
when removed from bovine hosts. 
Dates of moulting 
--^ Range in Number moulted 
Date nymphs 
-State of 
No. col- 
first 
last 
moulting 
-- 
--- 
collected 
engorgement 
leeted 
moulted 
moulted 
period 
males 
females 
total 
1911 
1911 
1912 
(days) 
Nov. 14 
1/2 to fully 
20 
Nov. 23 
Jan. 19 
9-66 
10 
5 
15 
engorged 
Dec. 5 
1/2 to fully 
8 
Dec. 27 
Feb. 1 
22-58 
1 
6 
7 
engorged 
„ 6 
2/3 to fully 
11 
» 11 
» 11 
5-70 
2 
9 
11 
engorged 
Totals 
39 
13 
20 
33 
Ticks which moulted from the larval stage on the host began to 
transform to adults about eight days later (see Table X). Some 
nymphs, apparently not more than one half engorged when removed 
from hosts, moulted to adults. The removal of the engorged ticks 
from the host greatly delays moulting. The longest period from 
collection to moulting in the lots observed was 70 days (see Table IX). 
The Adult (PL X, figs. 8, 9 ; PI. XII, figs. 3-8): Immediately after 
moulting to adults, the colour of the extremities of both sexes is 
a translucent brownish-yellow, the bodies being darker; the caecal 
system is visible through the integument as dark bands. The specific 
name is based on the appearance produced by these bands. 
The engorged females are smaller than most Dermacentors. The 
length (including capitulum), width, and thickness, range from 8'6 x 5’7 
x 4’2 mm. to 10’9 x 8'0 x 5'2 mm., respectively. The colour of the body 
varies from pale bluish-gray to rather dark bluish-gray with an olive 
tinge on the dorsum. 
There appear to be rather more males than females, judging from 
observations of the tick on hosts and of specimens moulting off hosts 
(see Table IX). 
A number of records have been kept of the longevity of adults 
maintained on moist sand in the laboratory. Unfed males lived from a 
few days to 95 days. Some unfed females lived for 69 days and one 
became attached to a host 66 days after moulting to an adult. A 
