142 LIFE HISTORY OF NORTH AMERICAN TICKS. 
ARTIFICIAL CONTROL. 
The longevity and numerous hosts of this tick make starvation 
impractical. Where the injury is sufficiently great to warrant arti- 
ficial checks, hand picking, mopping, or dipping should be resorted 
. to. Animals should be treated as often as every 12 days in order 
to prevent the females from engorging. 
THE LONE STAR TICK. 
Amblyomma americanum (Linnezeus). 
This species receives its common name from the silvery spot on the 
apex of the scutum of the female. 
DESCRIPTIVE. 
Adult (Pl. XI, figs. 2, 3, 5-10) —Males from 2.5 by 1.5 mm. to 
3.5 by2.5mm. Females, unengorged, 3.5 by 2 mm. to 4 by 2.25 mm.; 
engorged, 10 by 9 by 5 mm. to 15 by 12 by 8 mm. Color brown; 
posterior lobe of the scutum of the female with a large silvery white 
spot; the dorsum of the male also has silvery white markings around 
its posterior margin. 
Nymph (Pl. XI, fig. 4)—Unengorged, about 1.5 by 1.25 mm.; 
hight brown, with much yellow (fulvous), scutum somewhat darker; 
the intestines, which show through, appear to be of a dark brown 
color; length of capitulum 0.41 mm. (from tip of palpi to base of 
emargination of scutum) ; scutum 0.86 mm. long by 0.699 mm. wide; 
engorged, about 4 by 2.5 mm. in the larger specimens, which usually ~ 
become females, and 3 by 2 mm. in the smaller, which usually become — 
males; color dark gray. The silvery white markings of the males and 
females do not become visible until a day or two prior to the shedding 
of the skin. 
Larva (Pl. XI, fig. 1)—Unengorged, 0.64 by 0.51 mm.; length of 
capitulum 0.185 mm. (from tip of palpi to base of emargination of 
scutum) ; scutum 0.235 mm. long by 0.832 mm. wide; body ovoid, 
brown, lateral margin of scutum darker brown. Engorged,1.5 by 
1 mm., ovoid. Most of the larve as they drop engorged are dark 
brown, eae but some have a pink color. 
qq  Bllipsoidal, yellowish brown to pale yellow, or pale brownish 
yellow, shining, smooth. The maximum size of 10 was 0.570 by 
0.431 mm.; minimum size 0.514 by 0.416 mm.; average size 0.544 
by 0.419 mm. 
HOST RELATIONSHIP. 
The type host for this species is not known. The species has a 
wide range of hosts, apparently attaching to almost any mammal with 
which it comes in contact. It has also been taken from birds. In 
about 75 records of collections of this species in the southwestern part 
