LIFE HISTORY OF NORTH AMERICAN TICKS. 97 
THE BIRD TICK. 
Hzmaphysalis chordeilis Packard. 
The common name of this species is applied on account of the fact 
that birds are its principal hosts. 
DESCRIPTIVE. 
Adult (Pl. VII, figs. 7, 8)—Males from 2.8 by 1.5 mm. to 2.9 by 
1.6mm. Scutum light gray in color, shading into amber anteriorly; 
marginal strip bluish white; legs and capitulum amber. Females, 
unengorged, from 2.8 by 1.4 mm. to 2.9 by 1.8 mm.; engorged, about 
9 by 6.6 by 4 mm.; reddish brown in color when unengorged, scutum 
without markings. 
Nymph (Pl. VII, figs. 9, 10) —Unengorged, 1 by 0.65 to 1.4 by 0.72 
mm.; light brown in color, scutum darker; engorged, about 2.43 by 
1.79 mm.; color dark gray. Capitulum 0.217 mm. in length (from tip 
of palpi to base of emargination of scutum); scutum 0.446 mm. long 
by 0.447 mm. wide. 
Larva.—Unengorged, from 0.552 by 0.402 to 0.574 by 0.430 mm.; 
body ovoid, yellowish brown; engorged, from 1.4 by 0.8 by 0.6 mm. to 
1.5 by 1 by 0.6 mm.; abdomen slate color. In most cases three distinct 
longitudinal white lines are to be seen on the dorsum; shield very 
dark brown, almost black posteriorly, shading to a pale yellow-brown 
anteriorly. The legs and mouthparts are translucent yellowish 
brown. Capitulum 0.125 mm. in length (from tip of palpi to base of 
emargination of scutum), scutum 0.240 mm. long by 0.308 mm. wide. 
Egg.—No eggs of this species have been seen by us. 
HOST RELATIONSHIP. 
The type host of this species is the nighthawk. The species has a 
comparatively wide range of bird hosts. Those species which are 
more or less ground-inhabiting seem to be more frequently infested. 
The immature stages of this tick are frequently found in large num- 
bers, usually attached to the heads of the hosts. They are very fre- 
quently associated on the hosts with the immature stages of Hema- 
physalis leporis-palustris. The following birds have been found to act 
as hosts: meadowlark, jackdaw, red-winged blackbird, marsh hawk, 
quail, and domestic turkey. Mr. Banks mentions having seen a 
nymph, probably of this species, from the killdeer. The examina- 
. tions of birds in Texas indicate that the meadowlark is by far the 
most commonly infested host. We also have a fairly reliable record 
of three adults of this species having been taken from a prairie 
chicken in Texas. As has been stated, the ticks are usually found to 
attach on the top of the head. They are also found around the eyes 
and ears and occasionally under the bill. 
21448°—Bull. 106—12——7 
