(184 INSECTS AFFECTING DOMESTIC ANIMALS. 
as with allied forms, the posterior pair strongest. Abdomen long, lateral angles pro- 
duced, bearing a short spine or tooth, a short stiff hair and along hair; a tuft of 
hairs on lateral angles of the eighth segment. Egg elongate ovate, surface smooth 
throughout except at the cap, which is strongly convex and has a row of perfora- 
tions near the attachment to the body of the shell. 
Length, 1.55 and 1.65; head, 0.35; thorax, 0.13; abdomen, 1.20; antennz, 0.20 mm. 
Width, 9.50; head, 0.20; thorax, 0.22; abdomen, 0.50 mm. 
Egg: Length, 0.73; width, 0.28 mm. 
This species is at once distinguished from all others known by the 
peculiar structure of the antenna, no other species described possess- 
ing the process and curved tooth of the basal joint. In form of head 
it approaches acanthopus, but is larger than that species and has the 
sternal plate of different form. The egg is longer, more attenuated at 
the base, and devoid of the surface markings characteristic of that 
species. Collected from a fox squirrel, Sciurus cinereus var. ludovicianus, 
at Ames, Iowa. ; 
LOUSE OF THE GRAY SQUIRREL. 
(Hematopinus montanus n. sp.) 
Head rounded in front, projecting well in front of antennz; antenne strong, basal 
joint without hooked tooth, a bristle at each side 
behind. Sternal plate very broad in front, contracted 
behind for half its length, almost fungiform, Ab- 
domen broad; hairs long, these on dorsum slightly 
irregular, mostly longer than length of segment, 
those at lateral angles longer. Length, 1.40 to 
1.50 mm. 
On Western Gray Squirrel, Fort Collins, 
Colo. (Baker). 
I have still another form sent me by Dr. 
A. Hassall, of Baltimore, which seems to 
difter from both this and the antennatus and 
to approach the lyriocephalus of Europe, 
Fic. 107.—Hematopinus montanus— but I have not been able to satisfy myself 
a ee aa with regard to its relationship. 
LOUSE OF THE WHITE-FOOTED MOUSE. 
(Hematopinus hesperomydis Osborn.) . 
Body elongate, general color golden yellow. 
Female.—Head subquadrate, rounded in front, a concavity for the rostrum, obtusely 
angulated on the posterior border; antenn set near the front; first joint large, short ; 
second longest, the rest nearly equal; fourth with a small tooth on the posterior 
border, terminal pit with several short hairs. Thorax shorter than the head, small, 
sternal plate cuneiform, obtusely angular, irregularly or obliquely truncate in front 
and sharply pointed behind; anterior legs small and weak, the middle ones some- 
what larger, the posterior pair much the largest, flattened; terminal joint of tarsas 
very broad and curved, opposing basal joint of tarsus and meeting tibial spur ia 
such manner that the three form almost a complete cylinder; abdomen oval elon- 
