92 CALIFORNIA STATE COMMISSION OF HORTICULTURE. 



The Phoridse, or humpbacked flies, is a family of small insects, the 

 larvae of which are parasitic. 



The Conopidse is a family of large-headed flies, any of which in their 

 mature form resemble wasps in general appearance, having the abdo- 

 men elongated and connected with the thorax by a slender pedicel. 

 They are common among flowers, and their larvae are parasitic on 

 bumblebees and wasps. 



The family (Estridse consists of the botflies. The members of this 

 family are medium to large in size, of heavy build, resembling bees in 

 general structure, and the family contains some of the worst pests 

 which our four-footed animals have to struggle against. In this family 

 is found the botfly of the horse, the warble of the ox, the sheep gadfly, 



and their kindred, which, in their 

 larval stage, live upon the intes- 

 tines or muscles of quadrupeds. 



The reproduction of these insects 

 is one of the freaks of nature, and 

 is accomplished in the most round- 

 about manner. The female of the 



ir^r M "* uei horse botfl y la y s her e ^ s on the 



legs or other handy portions of the 

 horse, and so well does the animal know his enemy that horses will run 

 in terror from them. The eggs are small yellowish bodies, furnished 

 with hooks, by which they are attached to the hairs of the horse, 

 usually the lower portion of the legs. It is wonderful, too, with what 

 rapidity a fly will attach her eggs to the selected spot. We have 

 watched them in action, and seen them dart at the spot and away 

 again, not even resting, but in the short contact an egg was securely 

 placed. The eggs are taken into the mouth of the horse, which licks 

 itself, and the moisture and warmth cause them to hatch at once. The 

 irritation occasioned by them causes the animal to swallow them and 

 then they attach themselves to the coating of the stomach, where they 

 remain until they have attained their larval growth, which requires 

 eight or ten months. They are then passed, and fall to the ground, 

 going through their pupa stage underground. 



The ox warble is also taken into the stomach of the animal, but 

 works its way between the muscles until it reaches the back, where, just 

 beneath the skin, it grows rapidly until it has reached its full larval 

 growth, when it enlarges an air hole, which it had already made in the 

 skin, and passes out, dropping to the ground and going through its 

 transformation underground. 



