300 ENTOMOLOGICAL NEWS. [November, 



third recorded instance of the metamorphosis of this fly having taken 

 place under artificial conditions. Two years ago, after many failures, I 

 was able to record my success, followed a few weeks later by Dr. Cooper 

 Curtice, formerly of the Bureau of Animal Industry, Washington. 



Dr. Curtice has made an exhaustive study of the life-history of this fly 

 known North and East as the oxwarble fly, here as the heel-fly, although 

 their identity was scarcely ever suspected until two years ago. I believe 

 that here the fly invariably deposits its eggs on the hair around the heel, 

 although the popular idea is that the fly actually stings the animal. The 

 cattle lick themselves, thus conveying the eggs into the mouth, the larva 

 making their way in between the walls of the gullet. Here they remain 

 some months, when they finally make their way up to the skin along the 

 back, where they bore through, remaining in the hole a little over two 

 months. When they first reach the skin they are quite white, but gradu- 

 ally color and form somewhat become a dark brown or black, and forcing 

 themselves out of their sacks fall to the ground. The skin of the larva 

 becomes hard and shell-like, and at the end of about six weeks the perfect 

 fly emerges. 



Although I know that in Penna. the backs of domestic cattle are often 

 badly infested with these larvae, showing that the fly is by no means rare, 

 yet I never saw that its presence caused any fright or even uneasiness, 

 whilst here it is so dreaded by cattle as to cause at times heavy loss to 

 stockmen. The time of the fly beginning and ending its attack is very 

 variable. I have seen cattle running from it as early as December, whilst 

 this year up to date (Feb. i5th) I have seen no indication of its presence. 



Cattle seem to become absolutely frantic from terror; a steer will be 

 quietly grazing, when suddenly he will spring forward head erect, tail 

 arched, and in a moment he will be madly rushing across the pasture, 

 probably to the creek, into which he \fill plunge, remaining for hours. If 

 the streams running through the pasture have muddy bottoms many weak 

 animals become mired and perish miserably unless discovered and pulled 

 out. As the fly generally appears towards the close of Winter, when 

 cattle are often comparatively poor and weak, the loss in this way would 

 be very serious but that stockmen have their men ride daily along the 

 banks of any boggy streams in order to rescue mired animals. 



When a cow-boy finds one unable to get out he uncoils his lariat, deftly 

 throws it over the horns, gives a turn or two around the pommel of his 

 saddle, and, calling on his pony, the animal, unless very badly mired, is 

 soon on the bank and in safety, and hereafter often comes the most diffi- 

 cult part of the business the letting go. In getting hold the cow-boy 

 has it all his own way, but once the animal is on solid earth again it forgets 

 its former peril, remembering only the terrible wrench to head and neck, 

 and proceeds to get even with its tormentor, with 'the result that the man 

 has sometimes to drop his rope and ride off trusting to its l>co uning 

 loosened and dropping off. Can any one suggest tin- reason why the fly 

 has such terrors for a Texas cow whilst in Pennsylvania she cares nothing 

 for it? GEO. W. HOLSTKIN. 



