CLASSIFICATION AND HABITS OF TICKS. 49 
The incubation period of eggs deposited during the middle of April 
was 6 weeks and of those deposited at the end of that month, 33 days; 
seed ticks that emerged the first of June lived for 10 weeks, when kept 
in test tubes on sand. 
Attempts were made to rear this species by placing seed ticks on 
dogs, but with poor success, as few seemed to attach. A dog was 
infested with seed ticks on May 29, but none could be found attached. 
On July 13, however, three adult ticks, two partially and one nearly 
fully engorged, were found between the toes on a front foot. One of 
the small ticks dropped July 14 and the engorged one on July 15. 
In the middle of October several males of this species appeared upon 
the dog, and these must have come from the above lot of seed ticks. 
They were found to change the location of their attachment from 
day to day. Our conclusion is that this species drops to the ground 
for both molts. 
Genus MARGAROPUS. 
Neumann stands alone in suppressing Margaropus (Boophilus) 
under Rhipicephalus. Although the two groups are closely related, 
it seems evident, not only from their structure but from their habits, 
that they form two distinct genera. 
Neumann’s latest arrangement of the forms is as follows: 
R. (M.) annulatus (Say). Southern United States. 
R. (M.) annulatus var. australis (Fuller). Australia, the Antilles, 
and South America. 
R. (M.) annulatus var. calcarata (Birula). North Africa. 
R. (M.) annulatus var. decoloratus (Koch). South Africa. 
~ R. (M.) annulatus var. caudata Neumann. Japan. 
R. (AL) annulatus var. argentina Neumann. Province of Buenos 
Ayres. 
Neumann considers that R. (J.) microplus (Canest.) is very prob- 
~ ably identical with R. (M.) annulatus var. australis. 
The first portion of this bulletin deals with the sole North American | 
representative of this genus, M. annulatus (see Pl. III, figs. 1, 3). 
Genus DERMACENTOR. 
This genus is characterized by the presence of cleft front coxe in 
both sexes, the fourth pair of an immense size in the male but normal 
in the female. The structure of the stigmal plate furnishes valuable 
characters in specific determination in this genus as do the porose 
areas. 
Salmon and Stiles in 1901 had but three species before them from 
the United States, which they identified as D. electus Koch (varia- 
bilis Say), D. reticulatus Neumann, and D. variegatus Neumann. 
5795—No. 72—07——4 
