512 



DISEASES OF CATTLE. 



THE HOENFLY (LYPEROSIA IERITANS).i 



This fly, now found nearly everywhere in the United States, was 

 introduced into this country from Europe about the year 1885. 

 Hornflies have the habit of clustering aljout the base of the horn 

 (fig. 7) , whence the name by which tliey are popularly known. They 

 do not damage the horn, and congregate there only to rest. 



In view of the general practice of dehorning cattle, the name horn- 

 fly is less distinctive than it once was. Moreover, hornflies rest on 

 other parts of the body as well as the horns. 



When resting, their wings are held down close to the body (fig. 6) ; 

 when feeding, their wings are held out nearly at right angles, ready 

 for flight. They puncture the skin and suck blood, usually attacking 



the upper parts of the body, 

 particularly those which 

 are out of reach of the ani- 

 mal's head or tail. Unlike 

 most flies, they remain on 

 the animal more or less con- 

 stantly, day and night. Ow- 

 ing probably to the irrita- 

 tion and annoyance caused 

 by these flies, cattle often 

 do not thrive as they should 

 during seasons when the 

 flies are numerous. The 

 hornfly has also been 

 charged with transmitting 

 diseases, such as anthrax. 

 The fly lays its eggs in 

 freshly dropped cow ma- 

 nure. They hatch in about 

 24 hours, and the larvae or 

 maggots in four or five days develop to the pupal stage, Avhich lasts 

 a Aveek or 10 days. From the pupal stage the mature fly emerges. 

 The entire process of development from the deposition of "the egg to 

 the appearance of the mature fly therefore may be completed in two 

 weeks, or even in a shorter time. To protect cattle from attacks 

 of the hornfly they may be treated with one of the remedies men- 

 tioned above (p. 510). Dipping cattle in a vat provided with splash- 

 boards set at the proper angle destroys most of the hornflies present 

 on the animals. Unless the splashboards are used all but a few of the 

 flies succeed in escaping as the cattle plunge into the batli and later 



r'n;. G — Uornfly (Lyperosia in-itans) in rest 



tion. Enlarged. (From Bureau of Entomology.) 



IQg POSI- 



1 For furtlier information consult Circular ] 15 of tlie P.ureau of Enlomology, 



