28 
NORTH AMERICAN FEVER TICK AND OTHER BPECIES. 
due to the fact thai, in lighl infestations with widely scattered ticks, 
fertilization is less likely to take place than in other cases where the 
males may lind the females more readily. We Lave beer unable to 
determine thai unfertilized females occupy longer in development 
than those thai are fertilized, bul our impression is that they dp. 
The table also shows that 1 he principal variation in the time of 
developmenl of the ticks of the same infestation lakes place not in 
the larval or nymphal but in the adult stage. 
Table VII. Development of Margaropus annulatus on steer at Dallas, '/'< i . 
Ap- 
,,h- 
When 
tion 
applied. 
No. 
1905. 
1 
Aug. 10 
2 
Sept. 27 
3 
Nov. 11 
1906. 
4 
Jan. 16 
5 
Mas .2 
6 
.June 29 
7 
Aug. 2 
8 
Sept. ") 
9 
Oct. 6 
10 
Nov. 29 
1907. 
11 
Jan. l 
First 
molt. 
Aug. 28 
Oct. i 
Nov. 22 
Jan. 25 
May 31 
Mini- 
mum 
larval 
stage. 
Days. 
12 
7 
11 
Vug. 10-11 
Sept. 12 
Oct. 14 
Dec. 8 
Jan. 8 
7 
8 
9 
Second 
molt. 
Sept. 
2 
Oct. 
12 
Nov. 
28 
Feb. 
3 
June 
6 
July 
1G 
A.Ug. 
18 
S.'pl 
22 
Oct. 
21 
Dec. 
14 
Jan. 
14 
Adults dropix'l. 
mum 
nym- 
phal 
stage. 
First. 
Lasl . 
Days. 
5 
8 
G 
Sept. Lfi 
Oct. 21 
Dec. 8 
Sept. _■:■ 
Nov. 8 
Jan. 9 
9 
6 
""i-s 
10 
7 
G 
Feb. 17 
June 14 
July 24 
Aug. 25 
Sept. 26 
Oct. 30 
Dec. 22 
Mar. 8 
June 30 
Aug. 5 
Oct. G 
Nov. 12 
Jan. 1 
6 
Jan. 24 
Feb. 3 
Mini- 
Xuin 
Period from 
mum '' ' attachment to 
I"" mov- dropping. 
aduith/ 01 
stage drop- Maxi- Mini- Aver- 
Dai/s. 
13 
n 
n 
9 
5 
14 
236 
200 
55 
Days. Days. 
33 
33 
4:; 
41.5 
HI 
31 
31.5 
26. 5 
30.5 
28 
a Removed. 
DEVELC )I\M E X T ( > V HOST. 
When the larval ticks find themselves on the host they rapidly dis- 
appear in the hair and attach themselves to tbe skin. They are 
principally found on such parts as the legs, belly, and dewlap that 
conic in contact with tbe bunches on the grass, but maybe found on 
any pari of the host. In cases of severe infestation they practically 
cover the entire surface of tbe body, even the eyelids being infested. 
In from 7 to 12 days the larval ticks molt and enter the nymphal 
stage, in which they have eighl instead of six legs. The nymphal 
stage i^ further distinguished from the larval stage by the presence of 
a pair of large stigmata quite in contrasl to the rudimentary organs 
of respiration of the larva. 
The second molt (from the nymphal to the adult stage) occurs in 
from five to ten days after the first. The nymph can be distinguished 
from the adult , which it resembles very closely, by the absence of any 
genital opening. The process of both molts is undergone by tbe 
females while the hypostome is firmly inserted in the skin of the host. 
The shed skin splits open along either side and drops oil" in two scale- 
like pieces. A portion of skin from the capitulum is also shed at tbe 
