PARASITIC INSECTS AND MITES 



237 



headed horse louse, //. macrocephalus; the long-nosed ox louse, 

 //. tenuirostris; the larg-e-bellied ox louse, H. eurysternus; the 

 H. stenopses of sheep ; //. suis of swine ; and the //. piliferus of 

 the dog. 



The common hiting lice (Fig. 63) that are found on domestic 

 animals are the T. pilosus and T. puhescens of solipeds, T. 

 scalaris of the ox, T. spcerocephalus of sheep and goats, T. laius 

 and T. suhrostratus of the dog and cat. Menopon palidum, 

 L'lpiurus rariahllis and Gon- 

 oides dissimilis are the com- 

 mon lice found on poultry. 



Symptoms of Lice. — The 

 s^Tnptoms of lousiness depend ^ 

 on the variety of lice present, 

 the degree to which the ani- 

 mal is infested with them, its 

 physical condition and tlie 

 care that it receives. Lice 

 multiply more rapidly and 

 cause greater loss during the 

 winter months than they do 

 in the summer, when the 

 animals are not housed and 

 the opportunity for infection 

 from the surroundings is not 

 so great. The sucking louse (Fig. G4) is the most injurious 

 and irritating. The irritation and loss of blood that the animal 

 may suffer when badly infested by this parasite may result 

 in marked unthriftiness. Young and old animals that are not 

 well cared for suffer most. The biting louse may bite through 

 the superficial layer of the skin, and cause the animal to bite 

 and rub the part. This irritation to tlie skin prevents the 

 animal from becoming rested, and after a time seriously inter- 

 feres with its thriftiness. 



Fig. 63. — Biting louse. 



