earest allied
to Pediculus.

[Illustration: 121. Louse of Domestic Fowl.]

The common barn-yard fowl is infested by a louse that we have called
Goniocotes Burnettii (Fig. 121), in honor of the late Dr. W. I. Burnett,
a young and talented naturalist and physiologist, who paid more
attention than any one else in this country to the study of these
parasites, and made a large collection of them, now in the museum of the
Boston Society of Natural History. It differs from the G. hologaster of
Europe, which lives on the same bird, in the short second joint of the
antennae, which are also stouter; and in the long head, the clypeus being
much longer and more acutely rounded; while the head is less hollowed
out at the insertion of the antennae. The abdomen is oval, and one-half
as wide as long, with transverse, broad, irregular bands along the edges
of the segments. The mandibles are short and straight, two toothed. The
body is slightly yellowish, and variously streaked and banded with
pitchy black. The duck is infested by a remarkably slender form (Fig.
122, Philopterus squalidus). Figure 123 represents the louse of the cat,
and another species (Fig. 124) of the same genus (Trichodes) lives upon
the goat.

The most degraded genus is Gyropus. Mr. C. Cook has found Gyropus ovalis
of Europe abundant on the Guinea pig. A species is also found on the
porpoise; an interesting fact, as this is the only insect we know of
that lives parasitically on any marine animal.

[Illustration: 122. Duck Louse.]

The genus Goniodes (Fig. 125, G. stylifer, the turkey louse) is of great
interest from a morphological and developmental point of view, as the
antennae are described and figured by Denny as being "in the males
cheliform (Fig. 126, _a_, male; _b_, female); the first joint being very
large and thick, the third considerably smaller, recurved towards the
first, and forming a claw, the fourth and fifth very small, arising
from the back of the third." He farther remarks, that "the males of this
[which lives on the turkey] and all the other species of Goniodes, use
the first and third joints of the antennae with great facility, acting
the part of a finger and thumb." The antennae of the females are of the
ordinary form. This hand-like structure, is, so far as we know, without
a parallel among insects, the antennae of the Hemiptera being almost
uniformly filiform, and from two to nine-jointed. The design of this
structure is probably to enab