192 INSECTS AFFECTING DOMESTIC ANIMALS. 
and often with a complicated structure, while the terminal segment of 
the female is bilobed. The species of Ornithobius are white or trans- 
parent and especially characterized by having sharp curved append- 
ages meeting in front of the clypeus. Trichodectes is at once known 
by the three-jointed antenne. Other genera of the family do not con- 
tain species infesting domestic animals, and hence need not be noticed 
here. 
LOUSE OF DUCKS AND GEESE. 
(Docophorus icterodes Nitzsch. ) 
This species has been recorded from so many different members of 
the order of birds containing the ducks and geese that it may be con- 
sidered as common to the order. It was described by Nitzsch in 1818, 
and has been mentioned by most writers on parasites since that time. 
It is about 1 mm. in length, and has the head and thorax of a bright 
reddish color with darker bands. The abdomen is white in the center, 
with broad, dark reddish, horny bands at the sides, with a darker spot 
atthe margin. It occurs commonly on our native ducks. 
LITTLE RED SWAN LOUSE. 
(Docophorus cygni Denny.) 
Notwithstanding the apparent abundance of this species, it does not 
appear to have been described before 1842, when it was described and 
figured by Denny (Monog. Anop. Brit., p. 95, pl. 1, fig. 1), but accord- 
ing to this author it was figured by Redi (Exper., 
Pl. LX, fig. inf.), which would carry its recognition 
back two hundred years. It is common on both 
the wild and domesticated swans, and Denny states 
that he has received it from the bean goose. 
| It is 1 mm. in length, of a robust form, the head 
th decidedly rounded in front, except at the extreme 
Fic. 112. — Docophorus tip, Where it is slightly excavated. In color the 
cygni (author's illus head, thorax, and legs are bright reddish brown, 
Le while the abdomen is white in the center and dark 
brown at the sides, the brown occupying hard plate-like portions at the 
side of each segment. 
The form and the distribution of these plates are shown in the accom- 
panying figure. ; 
LESSER CHICKEN LOUSE. 
(Goniocotes hologaster Nitzsch. ) 
This common species which lives upon the domestic fowl was recog- 
nized by DeGeer and by Nitzsch. It has been generally confused with 
another form, or rather another larger and perhaps more common form 
