1886.] Grosse’s Classification and Structure of the Bird-lice. 341 
only genus, characterized by three-jointed antenne and one- 
clawed feet; (2) Philopteride, s¢rzcté, with five-jointed antenne 
and two-clawed feet. 
The Liotheide have likewise two families: (1) Gyropus, the 
only genus, having one-clawed feet; and (2) Liotheide, strict, 
with two-clawed feet. 
Trichodectes and Gyropus occur only on mammals, the other 
genera only on birds, and are classified according to the presence 
or absence of appendages on the head (trabeculz) and their mo- 
tility, to the sexual differentiation of antennz, their attitude, the 
form of the head, the consistency of the thoracal somites and the 
form of the last abdominal somites. 
; PHILOPTERIDÆ, strictè. 
1. Trabeculæ motile, antennæ nearly alike in both sexes. ........++--Docophorus. 
2. Trabecule not motile. 
a. Antennz filiform, no sexual differentiation. 
(a) Hind-head rounded off, terminal somite of male rounded off. . Virmus 
(¢) Hind-head abruptly angled, abdominal somites fused in the middle 
Goniocotes. 
6, Antennæ of male forcipate by a process from the third segment. 
(a) Hind-head angled, terminal somite of female tubercle-like, of male 
unded o; oniodes. 
(2) Hind-head rounded off, terminal somite of male notched . . Lipeurus 
$ 
LIOTHEIDÆ, strictè. 
I, Mesothorax wanting, antennæ ORES concealed., x 
a. Head very broad, no orbital sinùs........... Eureum. 
4. Head elongated, with lateral is diced kwin ds. i 
(a) With sharply marked-off clypeus and shallow orbital sinus 
Lamobothrium. 
(4) With only wavy head-margins, and long lateral lobes on the labrum 
Physostomum. 
2. Mesothorax presen 7 
a. Mesothorax aR sharply marked-off, head three-sided, antennæ perse. 
Trin 
6. Mesothorax small , only indicated. 
Bs, (2) Orbit&l hay deep, antennz mostly elongated and visible. Co/pocephalum. 
oe i (4) Orbital bay very shallow or obsolete, antennz concealed.. -- Menopon. 
Grosse’s researches have been largely ona Todda found on — 
_ 4 pelican from Chili, closely related to Menopon and forming the a 
type of a new genus and species, Tetrophthalmus chilensis. The — 
male is 44% mma long, the female slightly less. He also con- — 
important emendations of our knowledge of the other 
_ Head. -—In Tetrophthalmus the head is somewhat constricte 
is broader than long, caning! convex above, concave below, and 
