112 LIFE HISTORY OF NORTH AMERICAN TICKS. 
yellowish or grayish brown; capitulum and shield light reddish brown; 
legs pale yellowish brown; engorged, grayish blue. Capitulum 
0.296 mm. long (from tip of palpi to base of emargination of scutum); 
scutum 0.478 mm. long by 0.455 mm. wide. ° 
Larva (Plate VIII, fig. 2).—Unengorged, about 0.547 by 0.413 mm. ; 
engorged, 1.5 by 0.75 mm. Color unengorged, capitulum and 
scutum dark reddish, legs a shade lighter, body almost colorless; 
engorged, light yellowish gray. Capitulum 0.148 mm. (from tip of 
palpi to base of emargination of scutum); scutum 0.296 mm. long 
by 0.341 mm. wide. 
Egg.—Ellipsoidal, deep yellowish brown, shining, smooth. The 
average size of 10 specimens measured was 0.542 by 0.418 mm. 
HOST RELATIONSHIP. 
The type host is the Virginia white-tailed deer, Cervus virginianus 
Boddoert [=Odontocelus americanus (Erxleben)]. Of the undomes- 
ticated animals the deer is the only host known. 
Bovines are the principal hosts of the species, but the tick also 
commonly attaches to horses and mules, and occasionally to sheep 
and goats. Only 4 engorged females have been taken by the writers 
from dogs, although numerous dogs have been examined and many 
attempts to induce this tick to attach to them have been made. 
Attachment to a human host very rarely takes place. 
GEOGRAPHICAL DISTRIBUTION. 
(Fig. 7.) 
Florida is the type locality. This species is limited in distribution 
to the Lower Austral and a very small portion of the Upper Austral 
and Tropical Zones. The species occurs in greatest abundance in 
the humid or Austroriparian division of the Lower Austral Zone. It 
is known to occur only in the southern United States and Mexico, 
although it has been carried from this territory upon the host. 
The quarantine placed upon southern cattle by the United States 
Department of Agriculture now prevents its introduction into the 
Northern States. 
LIFE HISTORY. 
Owing to the economic importance of this species its life history 
and habits are better known than those of any other tick. Studies 
of its biology have been made by Curtice (1891), Morgan (1898), 
Newell and Dougherty (1906), Hunter and Hooker (1907), Cotton 
(1908), Graybill (1911), and others. 
The egg (Tables XX XVII-XXXIX).—During the warmer months 
o: the year oviposition commences on the second or third day after 
dropping. Occasionally eggs may be deposited on the day following 
dropping. During the winter months the preoviposition period is 
