FARMERS BULLETIN 009. 



yellowish white. 

 They may be dis- 

 tinguished readily 

 from the sucking 

 species by the gen- 

 eral shape of the 

 head and body and 

 by the color. 



The life history is 

 similar to that of 

 the sucking lice. 

 The average period 

 of incubation is 

 probably about 10 

 days. The eggs or 

 " nits " are shown in 

 figure 4. 



NATURE AND 

 HABITS. 



FIG. 3. Biting louse of cattle (Trichodcctes scalaris). 

 (Magnified about 20 times.) 



Female. Each S p e cies of do- 

 mestic animals has 

 its own particular 



species of lice, and except in accidental cases cattle lice are found 

 only on cattle. They increase very rapidly in number on cattle dur- 

 ing dry, cold weather when the hair is long, but when green feed 

 comes in the spring and the animals shed the 

 old coat of hair the lice become less numerous 

 and seem to disappear, and they are seen 

 rarely during the summer months. Some 

 of the lice, however, usually remain on the 

 animals throughout the summer, but not in 

 sufficient numbers to do harm, as they do not 

 increase rapidly while the animals are on 

 green feed and in a thriving condition. With 

 the coming of winter, when conditions again 

 become favorable, the lice increase very 

 rapidly. Treatment therefore should be 

 applied in the fall while the weather is suit- 

 able and before the lice have become nu- 

 merous enough to cause injury. 



The sucking lice usually select locations 



, , , . . FIG. 4. Eggs or nits of biting 



where they are partly protected from the i ou se on a hair. The two 

 efforts of the animals to dislodge them. The lower e - s * "nhatched ; 



, . , . , ' ' - the upper one has hatched. 



favorite locations are the sides 01 the neck, (Magnified about 20 times.) 



