256 INSECTS AFFECTING DOMESTIC ANIMALS. 
north into Germany and England. In the United States it is common, 
I believe, as far north as St. Louis. 
It is found mainly in pigeon houses and sucks blood for nourish- 
ment, but it is capable of living an almost incredible length of time 
without food, instances being on record where it has been kept in con- 
finement without food for two years, during which time the molts recur 
at frequent intervals. 
The body is projected in front far in advance of the head, the color 
is a deep gray, the form ovate, and the length about one-eighth of an 
inch. 
A related species, Argas persicus, is said to be a pest in houses in 
Persia, and Argas moubata in Angola, and Argas talaje in Guatemala, 
are equally annoying in their respective habitats. 
THE AMERICAN ARGAS. 
(Argas americanus Pack.) 
This species was described by Packard in the Report of the Geolog- 
ical Survey of the Territories for 1872 (p. 740), but rather oddly both 
Murray and Railliet credit it to Riley. Railliet, however, cites Hopeas 
authority for its reference to radiatus. 
It is reported by Dr. Francis as destructive to chickens in parts of 
Texas, and in the original description it is said to have been collected 
with the cattle tick from cattle. 
Packard’s description reads: 
Body very flat and thin, oval, with the head and mouth parts concealed by the 
overreaching dorsal portion of the body, which is bent upward around the margin, 
though the edge is not revolute. Body above covered with very numerous little 
round pits, large in the middle and becoming smaller on the edge. There are two 
large, conspicuous pits on the middle of the anterior third of the body, just in front 
of the middle transverse curved row of six smaller pits, three on each side. Behind 
are six prominent pits, three on each side. On posterior third of the body are rows 
of these punctures radiating outward. The edge of the body is roughly granulated. 
Margin of the body beneath pitted as above. Smooth between the legs and on the 
head. Palpi long and slender when stretched out, not reaching the edge of the body. 
Legs large and stout, hind pair just reaching edge of body. Claws long and curved, 
as usual. 
Length, 0.26 inch; breadth, 0.15 inch. 
Shown in Pl. IT], fig. 3, drawn by Dr. Marx, the figure, however, not 
indicating the radiation of the pits on the posterior part of dorsal 
surface described and figured by Packard, and which gives the name — 
radiatus. 
Two related species, the Rhynchoprium spinosum Marx, from Texas, 
and the Ornithodorus americanus are illustrated in PI. III by the 
lamented Dr. George Marx. 
