Way down through the hairs until the}' can insert their beaks in-' 

 to the skin ; apparently they then inject a little poisonous secre- 

 tion which causes irritation and inflammation and a flow of blood 

 to the spot. This blood is then sucked into the stomach of the 

 fly. When once established they remain for some time ; and 

 commonly come into the barn at milking time still in position on 

 the cows. Cattle thus attacked become restless and irritable 

 and if the flies are very numerous, they lose flesh and give less 

 milk. 



The life-history of the Horn Fly may be briefly suminnrized 

 as follows : The female flies deposit the small, wliitish eggs 

 (Fig. 2, (i) in freshly dropped cow dung. Within a day these 

 eggs hatch into little whitish maggots or larvae, thnt become 

 full grown in a week or ten days. They are then three-eigths 

 of an inch long, and of the form shown at h, Fig. 2. These 

 full-grown larva? change to the third stage of insect existence — 

 that of the chrysalis or pupa — at or just below the surface of 

 the ground. They are then brown in color and of the shape 

 shown in c. A few days later a fully developed Horn Fly 

 emerges from each of these brown cases, and thus completes 

 the round of the insect's life history. 



Fig. 2 — The Horn-Jly : a, »'gg ; h, larva; <\ pupnrimii ; J, 

 adult in biting position. Maguilied. 



