78 



PARASITES OF THE DOMESTIC ANIMALS 



or condition and everywhere where these animals are found. The 

 intensity of the pruritus produced is proportionate to the parasite's 

 size, the skin, as they increase in nuniberS; becoming covered with 

 papules and scales. The constant itching and worry, which. seems to 



be most severe at night, is evidenced 

 by the restlessness of the animals 

 and their violent scratching against 

 any available object. Such a con- 

 dition seriously interferes with the 

 growth and fattening of hogs, and 

 young pigs especially will often 

 succumb to loss of blood and ex- 

 tensive irritation and excoriation 

 of the skin. 



Pediculosis of the Dog 



Dogs have one sucking louse, 

 Linognathus piliferus and one biting 

 louse, Trichodectes latus. 



1. Linognathus piliferus (Haema- 

 topinus piliferus). Pediculidae 

 (p. 70). — Head thick, about as wide 

 as long, rounded 

 in front. The 

 thorax anteri- 

 orly is but slightly wider than the head; abdomen 



elongate oval in outline, the margins of the segments 



appearing somewhat rounded ; stigmata marginal and 



distinct. The general color is yellowish white. The 



female is 2 mm. ; the male L5 mm. in length (Fig. 46). 

 2. Trichodectes latus. Philopteridae (p. 71). — 



Entire insect broad and short; more than half as 



broad as long. The head large, slightly rounded in 



front, and broader than long. The abdomen of the 



female is broad and somewhat globular in outline. 



The median abdominal bands or spots are absent. 



The general color is bright yellow (Fig. 47). 



Dogs do not seem to be as seriously affected as Bureau of Entomoi- 



other animals by the presence of lice. The sucking °^^' ^- ^- ^^p*' °^ 



louse is the more tormenting, and is usually found 



about the chin, under part of the neck, and breast, though, with the 



biting louse, it may be found on any part of the body. The biting 



species is most often found upon puppies. 



The biting louse infesting dogs is particularly of medical interest in 



Fig. 45. — Haematopinus suis (from 

 jDhotograph of mounted specimen, bv 

 Hoedt). 



Fig. 46. — Haemato- 

 pinus piliferus (after 

 Osborn, Bui. No. 5, 



