ORDER HEMIPTERA. 
SUBORDER PARASITA. 
This group includes the suctorial lice, confined to mammals; they 
are strictly parasitic insects, being confined to their hosts constantly, 
and deriving ali their nourishment from them. They are wingless, and 
the mouth parts consist of a tubular suctorial organ. 
This suborder contains but two families, the first of which, the 
Polyctenide, contains, so far as known, but twospecies, 
both of which are confined to bats, one in Jamaica and 
the otherin China. These do not properly fall within 
the province of this paper, and it will not be neces- 
sary to give them further consideration. 
FAMILY PEDICULIDZ—THE SUCTORIAL LICE. 
This family includes nearly all the species of the 
suborder and all that come within the limits of this 
paper. 
We need only add to the character above given the 
short rostrum without joint and the tarsi adapted to 
clasping and holding to hairs. 
The eggs, “nits,” are attached to hairs by a glue- 
like substance, and the young lice when hatched re- 
semble the adults except in size. As the entire life 
of the parasite is passed upon the same animal or on 
another animal of the same kind, its range of habit 
is easily stated. 
But very few of the species are ever found upon 
any other species of animal than that which they £ 
normally infest, and if so always upon very nearly f 
related species. Whether this is due to differences 
in the thickness of the skin, of temperature, of the 
size of the hair to which they must adhere and to 
which their feet are adapted, or to some subtle dif: / 
ference in the odor or taste peculiar to their partic- 
ular host which leads them to discard all others, we | 
are unable to say. ae aha . 
The mouth parts are necessarily capable of great peaicuiue sais 
extension in order to reach the blood of their hosts. img rostrum and extensile 
Uhler says (Standard Nat. Hist., 11, p. 209): «A ‘Po ~Steatly enlarged. 
fleshy unjointed rostrum, capable of great extension by being rolled in- 
7 
