CERTAIN PARASITIC INSECTS. 93 
lip, or labrum, lying under the clypeus ; mad, the mandibles ; 
max, the maxille ; 7, the lyre-formed piece ; pl, the “plate,” 
and v, the beak or tongue. (This, and Figs. 20, 21, 22, are 
from Melnikow). 
We will now describe some of the common species of lice 
found on a few of our domestie animals, and the mallopha- 
gous parasites occurring on certain 
mammals and birds. The family 
Pedieulina, or true lice, is higher 
than the bird lice, their mouth parts, 
as well as the structure of the head, 
resembling the true Hemiptera, es- 
pecially the bed bug. The clypeus, 
or front of the head, is much smaller 
than in the bird lice, the latter retaining the enlarged fore- 
head of the embryo, it being in some species half as large as 
the rest of the head. ; 
All of our domestic mammals and birds are plagued by 
one or more species of lice. Figure 25 represents the 
Fig. 25. Hematopinus vituli (Linn.), which is 
brownish in color. As the specimen fig- 
ured came from the Burnett collection 
of the Boston Society of Natural History, 
together with those of the goat louse, 
the louse of the common fowl, and of 
the cat, they are undoubtedly naturalized 
here; the other specimens were collected 
by Mr. C. Cooke, and are in the Museum 
of the Peabody Academy of Science. 
The remaining parasites belong to the 
AS `  Skin-biting lice, or Mallophaga, and I 
Louse of Cow. will speak of the several genera referred 
to here in their natural order, beginning with the highest one 
and that which is nearest allied to Pediculus. The species 
of Docophorus, figured on PI. I, fig. 3, appears to be unde- 
scribed, and may be called D. buteonis. It lives beneath the 
Fig. 21. 32 
TE 
