198 LIFE HISTORY OF NORTH AMERICAN TICKS. 
third pair of legs, from which the body is very noticeably constricted 
posteriorly. 
Larva (Pl. XIII, fig. 6).—Unengorged (in balsam), 0.714 by 
0.470 mm.; engorged, 1.5 by 0.9 by 0.6 mm. Color, unengorged, 
yellowish brown; engorged, steel-gray. Capitulum 0.205 mm. long 
(from tip of hypostome to base of emargination of scutum); scutum 
0.290 mm. long by 0.372 mm. wide. 
Egg.—The average size of 10 eggs measured was 0.565 by 0.419 mm. 
Color yellowish brown to brown; shining, smooth. 
HOST RELATIONSHIP. 
The type host of this tick, the horse, is the principal host for the 
species. This tick has also been taken from the ears of the mule at 
Brownsville, Tex., and at Tampico and Victoria, Mexico, Bishopp 
found it commonly in the ears of both the mule and the ass. It prefers 
the inside of the ears as a place for attachment. Hooker has found 
a number of specimens attached in the horse’s mane between the 
ears and several to the belly. This, however, was due to the fact 
that the ears were literally filled with ticks so that there was no 
place in the ears to which they could attach. In Texas several 
larve have been taken from the ear of a goat. The tick has also 
been taken from the ears of the ox and of a calf. A single specimen 
in poor condition, but apparently of this species, was taken at Kerr- 
ville, Tex., by Mr. F. C. Pratt from a deer skin that had been’ 
removed in January. In our studies we have found them to attach 
to the scrotum of a bovine and develop to engorged adults. 
GEOGRAPHICAL DISTRIBUTION. 
(Fig. 17.) 
Jamaica and Santo Domingo are the type localities for this species. 
In the vicinity of Brownsville, Tex., it is an important pest to horses 
which run in pastures; it has also been taken at Harlingen and at 
Corpus Christi, Tex. A single specimen which appears to be this 
species was collected at Kerrville, Tex., but the species has not been 
found during subsequent collections in that vicinity. There seems 
to be much doubt of the correctness of the record of this species 
from Arizona. The tick was found in abundance at Victoria and . 
Tampico, Mexico, but careful search for the species failed to reveal 
its presence on the plateau in the central and northern parts of that 
country. It has been recorded from Guatemala, Panama, and Costa 
Rica in Central America and from Cuba, Jamaica, Haiti, Santo 
Domingo, and Trinidad in the West Indies. It appears to be a 
serious pest in Cuba and Jamaica. 
