120 Book-lice and Bark-lice; Biting Bird-lice 
bands, and a white region in the middle of the abdomen. Trinoton luridum 
is another common duck-louse unusually large, being from 4 to 5 mm. ( 5 in.) 
long and readily distinguished by the triangular 
head with lateral swellings, and the abdomen with 
pronounced blackish-brown transverse bands. 
Fig. 
Fig. 152. 
Fig. 148.—A biting louse of pigeons, Lipeurus bacillus. (Natural size indicated by line.) 
Fig. 149.—Biting louse of the dog, Trichodedes latus. (After Nitzsch; natural size, 
1 to 1.5 mm.) 
Fig. 150.—Biting louse of the horse, Trichodedes parumpilosus, male. (After Morse; 
natural size shown by line.) 
Fig. 151. —Biting louse of cattle, Trichodedes scalaris. (After Lugger; natural size, 1.5 
to 2 mm.) 
Fig. 152.—Biting louse of fringilline birds, Docophorus communis. (Natural size in¬ 
dicated by line.) 
