Book-lice and Bark-lice; Biting Bird-lice 
11 9 
C. Forehead evenly rounded, without lateral swellings; antennae projecting 
slightly beyond border of the head. Colpocephalum. 
CC. Forehead with strong lateral swellings. 
D. Mesothorax separated from metathorax by a suture_ Trinoton. 
DD. Meso- and metathorax fused; no suture. L^emobothrium. 
BB. Ocular emargination absent or very slight. 
C. Sides of the head straight or slightly concave, with two small laterally 
projecting labral lobes. Physostomum. 
CC. Sides of the head sinuous; forehead without labral lobes. 
D. Ocular emargination filled by a strong swelling; sternal markings 
forming a quadrilateral without median blotches. Nitzschia. 
DD. Ocular emargination without swelling, hardly apparent or entirely 
lacking; median blotches on sternum. 
E. Very large; with two-pointed appendages on ventral aspect 
of hind head; anterior coxae with very long lobe-like append¬ 
ages. Ancistrona. 
EE. Small or medium; without bi-partite appendages of hind head. 
Menopon. 
The Mallophaga most likely to come under the observation of people 
not collectors of birds are the species which infest domestic fowls and mam¬ 
mals, and the following few descriptions and figures of particular species 
are therefore limited to such kinds. 
The most notorious member of the order is the common chicken-louse, 
Menopon pallidum (Fig. 146). It is of a pale straw-yellow color, from 
1 mm. (-gig- in.) to 1.5 mm. 
in length, and is an un¬ 
usually swift and active 
little pest. Other Mallo¬ 
phaga infesting chickens 
are Goniocotes hologaster, 
recognized by its squarish 
head with angulated 
temples, and Lipeurus 
variabilis, 2 mm. (y 1 ^ in.) 
long and slender, with dis¬ 
tinct black markings on 
the otherwise smooth, 
white body. 
Ducks are infested by 
several species. Com¬ 
mon among them is the 
little Docophorus icterodes 
(Fig. 147), 1 mm. (- 2 \ in.) 
long, with head curiously 
expanded and rounded in front, darkish-red head, and thorax with darker 
Fig. 146. Fig. 147. 
Fig. 146.—The biting chicken-louse, Menopon pallidum. 
(After Piaget; natural size, 1 to 1.5 mm.) 
Fig. 147.—The biting louse of wild ducks, Docophorus 
icterodes. (Natural size indicated by line.) 
