THE RABBIT TICK, 89 
Genus HH MAPHYSALIS Koch. 
Two species of the genus Hemaphysalis occur in the United States 
both of which are quite widely distributed. One of the two (Hzxma- 
physalis chordeilis) is of economic importance on account of its habit 
of attacking turkeys. The life history and habits of 3 exotic species 
have been studied, namely, H. leachi, the active agent in South 
Africa in the transmission of canine piroplasmosis, by Lounsbury 
(1902, 1904, 1905), H. prozima in Brazil by Rohr (1909), and H. 
punctata, which has been found by Stockman (1908) to transmit 
bovine piroplasmosis. This latter species has recently been reported 
by Hadwen (1910) to occur in Manitoba. It must have been intro- 
duced from abroad, probably on cattle from England, where it is a 
very common pest. All three of these foreign species, as well as the 
two species (H. leporis-palustris and H. chordeilis) which have been 
studied by us drop from the host for both molts. One of the authors 
(Hooker 1909a, pp. 252-253) was led to believe that this species molts 
on the hosts on account of molted skins of larve being found on the 
heads of quail associated with larve and nymphs belonging to the 
genus Hemaphysalis. We have since reared H. chordeilis and as we 
have had considerable numbers of both the larve and nymphs to 
drop from the hosts engorged and then molt, we must conclude that 
the skins found on the quail were shed by individuals of some other 
bird-infesting species. 
THE RABBIT TICK. 
Hemaphysalis leporis-palustris Packard. 
The rabbit tick (Hemaphysalis leporis-palustris Packard) is so 
named from the fact that it is the most widely distributed and common 
tick which attacks the rabbit in the United States. 
DESCRIPTIVE. 
Adult (Pl. VII, figs. 4-6).—Males from 1.6 by 1 mm. to 2.25 by 
1.25mm. Females, unengorged, from 2.25 by 1.25 mm. to 2.5 by 1.5 
mm.; engorged, from 6 by 3.5 by 2.5 mm. to 11.3 by 7.5 by 5.3 mm.; 
males and females very dark brown or black in color with no light 
markings; engorged females slate color. 
Nymph (Pl. VII, figs. 2, 3).—Unengorged, about 1.33 by 0.8 mm., 
dark reddish brown; engorged, 2.5 by 1.75 mm., dark bluish gray to 
almost black; capitulum 0.218 mm. in length (from tip of palpi to 
postero-lateral angles of basis capituli); scutum 0.422 mm. long by 
0.436 mm. wide. 
Larva (Pl. VII, fig. 1).—Unengorged, about 0.534 by 0.385 mm.; 
dark smoky brown; scutum lighter in center; engorged, about 1.33 
by 0.88 mm; ovoid, very dark brown to black, often with a pink tinge 
