16 



farmers' bulletin 857. 



Fig. 7. — The green-bottle fly. Enlarged. 



screw- worm fl}'. (See fig. 7.) 

 Its color ranges from a brilliant 

 bluish green to a dark metallic 

 bronze green. It is without 

 stripes or other markings. 



The adult flies usually ap- 

 pear during the first ts'arm 

 days of spring and are pres- 

 ent throughout the summer, 

 though they seldom become as 

 numerous as the screw-worm 

 fly or black blowfly. T^e length 

 of time required for 'develop- 

 ment is about the same as that 

 required by the black blowfly. 

 The maggots breed exclusively 

 in animal matter. 



THE GRAY FLESH FLIES. 



There are two or more species ^ of this group of flies which occa- 

 sionally breed in living animals, apparently attacking only old fester- 

 ing wounds. They are of comparatively little importance, and since 

 there are a great number of different kinds of flies of this group, some 

 of which are not at all injurious, it is hardly necessar}^ that the stock- 

 men learn to recognize them. Their size varies considerabl}^ from a 

 little larger than the common house fly to somewhat larger than the 

 black blowfly. The color usually is uniformly gray, with black 

 stripes on the back. One of these flies is shown in figure S. 



Many of the members of this group of flies retain the eggs in the 

 abdomen until they hatch, and thus bring forth living maggots. 

 Those species which attack living animals breed in decaying animal 

 matter and their life history is almost the same as that of the screw- 

 worm fl}^ The flies seldom become ver}' numerous, and in most of 

 the cases in which they are found in living animals they are located 

 in old festering wounds or the young are deposited after a sore has 

 become infested by screw'-worms. These flies seem to be able to with- 

 stand the hot, dry weather of midsummer in the Southwest and prob- 

 ably are responsible for man}' of the cases of infestation of animals 

 during such periods. 



METHOD OF CONTROLLING MAGGOTS. 



The black blowfly, the bluebottle fly, and the flesh flies are carrion 

 breeders. They attack wounds on living animals mainlv as a result 

 of the presence of the flies in abnormally large numbers. Therefore it 



ma Aldl'ich. /s'. tiihrrnna vai 



racciiifiidrx Aldri 



