93 



THE HORN FLY. 



{Hwmatohia svrnita Kobiuean-Desvoidy.) 



Fig. 11.— H.TJMATOlilA SERUATA : 



larged. (OriKiual.) 



a, csj 



b, larva; c, pui)aiiuin ; d, adult in biting position — all en- 



Our knowledge of this pest is now sufficiently far advanced to enable 

 us to present a preliminary article giving the main facts ascertained. 

 A more complete article will, however, be published in our annual report 

 for the year. 



FIRSl - APPEARANCE — SPREAD — INVESTIGATION. 



Our attention was first called to this pest in September, 1887, when 

 Mr. I. W. Nicholson, of Camden, N. J., wrote us under date of September 

 22, as follows : 



Herewith I send some specimens of flies which appear to have made their first ap- 

 pearance about the middle of August. They are very annoying to cattle, but rarely 

 settle upon the horses or mules. They gather in patches or clusters particularly upon 

 the legs, and are very active. I should like to know if they are common in other 

 parts of the United States. They appear to be very numerous in all the counties near 

 Philadelphia, yet I have seen no person who has observed them before this season. 



Later letters the same season from Mr. Nicholson mentioned the com- 

 mon habit of clustering upon tlie horns, and the fact that after a severe 

 frost in the middle of October the fly disappeared. 



May 15, 18S8, the same gentleman wrote us that the flies had promptly 

 made their appearance May 10, or a little before, in great numbers. A 

 few days later we heard of the same insect in Harford County, Md., 



