HEMIPTERA. 179 
one escape the scalding trough and succeed in finding another host. 
Of the vast number of hogs shipped to market and slaughtered at the 
great packing houses, none can bequeath the insects they have nurtured 
to their followers. The amount of injury and the consequent need of 
precautionary measures are therefore much less for this species than 
for many others. 
This is one of the largest species of the family, full grown individuais 
measuring a fourth of an inch or more in length. It is of a gray color, 
with the margins of the head and thorax and most of the abdomen 
dark. The head is quite long, the sides nearly parallel, with strong 
eminences just back of the antenne, which are set on the sides of the 
head, midway from rostrum to occiput; the legs are lighter, with dark 
bands at the joints; the spiracles are inclosed by a black chitinous 
Fic. 102.—Hematopinus urius: a, female; b, ventral view of posterior segments of male; c, leg, show- 
ing protractile disk of tibia—enlarged (author's illustration). 
eminence, and there is a broad black band on the last segment, broken 
near the middle. (See fig. 102.) 
The male has the abdomen marked beneath with a large black area 
extending forward from the end of the terminal segment, so as to occupy 
the central portion of the last three segments. 
There is a curious provision in the feet for strengthening the hold 
upon the hair, which does not seem to have been hitherto described. 
It consists of a circular pad-like organ or disk in the outer portion of 
the tibia, which is received in a conical cavity in the end of the tibia, 
and which can be forced out so as to press upon the hair held between 
the claw of the tarsus and the end of the tibia. Ordinarily, and always 
