38 



CIRCULAR 148, U. S. DEPARTMENT OF AGRICULTURE 



The biting lice of horses deposit their eggs in the same general man- 

 ner as the sucking louse. The period of incubation is probably from 

 8 to 10 days. These lice may live as long as 10 days when separated 

 from the host animal if kept on tufts of hair, but most of them die in 

 5 or 6 days. 



Daring cold weather, when the hair on horses is long, lice increase 

 very rapidly; but when the animals shed their hair in the spring the 



A 



B 



Figure 25. — Biting louse of horses {Bovicola pilosa): A, Male; B, female, 



(Magnified 2 5 times.) 



parasites seem to disappear. Some of the lice usually remain on the 

 animals throughout the summer, but not in sufficient numbers to cause 

 annoyance or to be easily detected. The animals, therefore, usually go 

 into the winter infested. Since the most efficacious remedies are 

 liquid dips, which cannot be used safely on horses during cold weather, 

 fall dipping should be practiced whenever horses have been lousy at 

 shedding time. 



