194 Forty- fifth Report on the State Museum. 



Mr. A. J. Fly, of Delta, Oneida county, writes as follows: 



I write to you for information in regard to a fly, which made its 

 appearance in these parts about a year ago, and is proving a source of 

 much damage to the dairymen and of suffering to the stock. The fly 

 has increased very fast and attacks the cattle in swarms, causing some- 

 times large, raw sores on the shoulders and by the root of the tail, and 

 also by the navel. They also cover the horns at times. They apparently 

 attack fat cattle as readily as those in poor flesh. White and light colored 

 cattle do not seem to be as much attacked as the black or dark ones. 

 On spotted cattle the flies are sometimes thick on the black spots, while 

 there are hardly any on the white. The fly seems more hardy than our 

 common one, and takes more to kill it. If there is anything that can 

 be done to get rid of this plague, our dairymen would be glad to know 

 it, and avail themselves of the information, that they may relieve their 

 cattle which are suffering greatly day and night. 



The injuries from the attack of this fly do not result in the death of 

 the infested animals, as was first reported, but they occasion large sores 

 upon the body in various places, and from the irritation and inflamma- 

 tion that the myriad flies cause, there follows a great falling off in the 

 amount of milk given — variously estimated at from one-third to one- 

 half. The cattle also lose materially in flesh. 



In New Jersey it has been found that the fly was most troublesome 

 in June and early July, and that after the middle of August it gave 

 comparatively little trouble. But even if you are to escape from any 

 serious further harm from it this year, you should d> what you can to 

 prevent its continued multiplication. 



Knowing that the fly deposits its eggs in the fresh droppings of the 

 cattle, and mostly during the night, and that it lives and matures 

 therein, I would urgently recommend that every morning, in infested 

 localities, these droppings be carefully and thinly spread in the fields, 

 so that it may quickly dry. The eggs and the larvae would die in the 

 dry material and could not mature therein. Another method of killing 

 the insect in its early stages, but perhaps not so good as the preceding, 

 is to scatter lime over the fresh droppings. To prevent the fiies from 

 biting the cattle, I know nothing better than once a week going over 

 the bodies with a sponge dipped in whale-oil in which some carbolic 

 acid has been mixed, only applying it to the tips of the hairs. I have 

 -treated of this fly, and given figures of it, in my Fifth Report on the 

 Insects of New York, 1889, pp. 220-227. Possibly you might make 

 •some extracts from this, which would be serviceable and interesting to 

 some of your readers. 



Very truly yours. 



