402 STATE AGRICULTURAL COLLEGE BULLETINS. 



resting position. Most of them had left the dung at the expiration of a 

 minnte. Every individual had returned to the cow, however, in a little 

 over a minute." This transpires mostly late in the forenoon, and as high 

 as three hundred eggs have been found in a single dropping. The eggs 

 hatch in about twenty-four hours and grow into yellowish white footless 

 larva3, three-eights of an inch in length, tapering gradually to a pointed 

 head. They then shrink into red-brown barrel-like puptie, and later appear 

 as a tly, completing the cycle of life in from ten to seventeen days. In 

 this way it is estimated there will be at least eight generations through a 

 season. With such rapid reproduction, it is easy to account for the sud- 

 den appearance of such great numbers. 



REMEDIES. 



/ 



So far preventatives or repellants have been found to be preferable to 

 substances that will kill the flies. Greasy substances of almost any kind 

 prove to be the best preventatives. Dr. Riley says, "A number of experi- 

 ments were tried in the field with the result that train oil alone, and train 

 oil with a little sulphur or carbolic acid added, will keep the flies away 

 for five or six days, while with a small proportion of carbolic acid it will 

 have a healing effect upon sores which may have formed. * * * Train 

 oil or fish oil seems to be more lasting in its effects than any other of the 

 substances used." 



"X. O. Dust" is recommended highly by Prof. Smith (loc. cit.) for 

 killing the flies by keeping the cattle well dusted with it. 



The most certain means of destruction is to kill the flies in the early 

 stage. This can be accomplished by throwing a shovel full of lime or 

 land plaster upon each dropping made by the stock. They will be found 

 most common in shady places that the cattle frequent, and by treating 

 them in this way once in two or three days, while the dung is yet fresh, 

 the fly will be destroyed in large numbers while still in its infancy. 



Prospects are that if we can stay the fly off for a few years, it will then 

 not trouble us so seriously. The following recently received from Prof. 

 Smith is encouraging. " For the past two or three years the Horn Fly has 

 been no more troublesome in this state (New Jersey, where it first 

 appeared) than the ordinary cow fly, Stomoxys calcitrans. It is in new 

 localities that it seems to be most troublesome, becoming gradually less 

 abundant after the third or fourth year." 



G. C. DAVIS. 



