I2O 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. 150. 



FIG. 152. 



FIG. 148. A biting louse of pigeons, Lipeurus baculus. (Natural size indicated by line.) 



FIG. 149. Biting louse of the dog, Trichodectes latus. (After Nitzsch; natural size, 

 i to 1.5 mm.) 



FIG. 150. Biting louse of the horse, Trichodectes parumpilosus, male. (After Morse; 

 natural size shown by line.) 



FIG. 151. Biting louse of cattle, Trichodectes 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.) 



