392 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



are much more serious pests, but fortunately they can be 

 controlled by concerted action on the part of all of the stock 

 owners in a community. After the larvae have attained con- 

 siderable size they are easily detected as they lie under the 

 skin on the backs of the cattle. When they are nearly ready 

 to issue they can easily be squeezed out and destroyed. They 



FIG. 180. Body-louse, Pediculus vestimenti. (About eighteen times 

 natural size.) 



may also be killed while still under the skin, but bad sores are 

 apt to result if this is done so it is much better to squeeze them 

 out. If all of the cattle owners in a community attend to this 

 early each spring, it is evident that the number of bot-flies 

 will soon be so reduced that they will cause little trouble. 



Lice. There are two distinct groups of wingless parasitic 

 insects commonly called lice. One group, the blood-sucking 

 lice, belongs to the family Pediculidce, order Hemiptera; the 

 other, the biting lice, constitutes an independent small order, the 



