46 LIFE HISTORY OF NORTH AMERICAN TICKS. 
great loss to poultry keepers, due to the removal by them of blood 
from the fowls, and more particularly because of the transmission 
by them of spirochetosis. 
The species are nocturnal parasites of chickens, geese, pigeons, 
and other birds and occasionally attack mammals. They remain 
hidden away by day in cracks and crevices, coming out at night from 
their hiding places to find the fowl host and engorge with blood. 
The life history and habits of Argas miniatus! as worked out by 
Lounsbury in South Africa are practically identical with those of 
miniatus as determined by the writers. This tick has been shown to 
be the active agent in the transmission of the causative organisms of 
spirochetoses (Spirochexta gallinarum and 8S. anserinum) of chickens, 
geese, and other fowls. 
In the larval stage Argas miniatus remains upon the host for 
several days to engorge, but in the nymphal and adult stages only a 
few hours at most are required. In miniatus, the only species of 
Argas whose life history has been followed, there is a second, and 
in about one-seventh of the individuals a third nymphal molt, as has 
been shown by Hooker (1909c). As adults, repeated engorgement 
takes place, each nearly always followed by the deposition of eggs. 
THE FOWL TICK. 
Argas miniatus Koch. 
The common name, fowl tick, is derived from the fact that this 
species feeds almost exclusively on domestic fowls and is an impor- 
tant enemy of them. 
DESCRIPTIVE. 
Adult (Pl. III, figs. 5-8)—Males, unengorged, 4.5 by 3.5 mm. to 
6 by 4.5 mm.; engorged, 5.5 by 3.5 by 2 mm. to 7 by 4 by 2.25 mm. 
Females, unengorged, 5 by 3 mm. to 8.5 by 5.33 mm.; engorged, 
6 by 4 by 2 mm. to 12 by 7 by 3 mm. 
Nymph (Pl. III, figs. 2-4).—Last stages (2d and 3d nymphal): 
Unengorged, 3 by 2 mm. to 4 by 2.75 mm.; engorged, (premales) 
5 by 3.5 by 2 mm. to 7 by 4 by 2 mm., (prefemales) 6 by 4 by 2 mm. 
to 8.5 by 5 by 2.6 mm. The normal brown color becomes purplish 
when blood is engorged. First stage: Unengorged, 2 by 1.25 mm. to 
2.5 by 1.5 mm.; engorged, 3 by 2 by 1 mm. to 4 by 3 by 1 mm. 
Brown, the margins of the body and legs colorless. 
Larva (Pl. IU, fig. 1).—Unengorged, about 0.8 by 0.6 mm., pale 
yellow to colorless; engorged, 2.2 by 1.5 mm. to 2.5 by 2 mm., dark 
blue. In one instance a larva dropped on the fourth night follow- 
ing attachment, and before assuming the flattened Argas shape. 
1 We have thought best to refer to the American fowl tick as A. miniatus; recent investigations, how- 
ever, indicate that it is synonymous with A. persicus, the name of the Old World fowl tick, 
