30 BOARD OP AGRICULTURE. 



him. At other times, this (Estrus gets between the fore-legs 

 of the horse whilst he is grazing, and thus makes its attack on 

 the lower lip. The titillation occasions the horse to stamp vio- 

 lently with his fore-foot against the ground, and often strike 

 with his foot, as if aiming a blow at the fly. They also some- 

 times hide themselves in the grass, and as the horse stoops to 

 graze, they dart on the mouth or lips, and are always observed 

 to poise themselves during a few seconds in the air, while the 

 egg is preparing on the point of the abdomen." The eggs are 

 darker colored than those of the common bot-fly, and contain 

 a nearly developed embryo, so that they very soon hatch, and 

 the young larvas are transferred to the mouth by the tongue, 

 and thence get into the stomach. 



In other countries there are still other species of bot-flies 

 that infest the horse, ass, and mule ; among them Gast- 

 rophilus inermis Br., which lives in the horse ; 6r. flavipes 

 Oliv., which inhabits the stomach of the ass and mule ; and a 

 species of Hypoderma, which lives beneath the skin of all three. 

 But I am not aware that either of these has been observed in 

 this country. 



The Meat-fly, Blowflies, etc. Figure 27. 



These flies are not true parasites, but naturally feed, while 

 in the larval state, upon decaying flesh and other animal 

 matter. Their larvae are, however, frequently Fio . 07 

 found in wounds and sores, both of animals 

 and men, feeding upon the purulent matter, 

 and when allowed to live undisturbed, not uii- 

 unfrequently attack the living flesh, when 

 their food becomes exhausted ; and in this wa, 

 if they gain access to wounds in large numbers, 

 they will not only greatly aggravate and enlarge 

 them, but in many cases, when neglected for a 

 short time, they have caused the death of men 

 and animals by actually eating away living tis- 

 sues. The females in this group of flies are 

 viviparous, the eggs being retained in capa- 



Figure 27. Larva or maggot of the Blue-bottle fly (Musca Ccesar Linn.), en- 

 larged. From Packard's Guide. 



