DIPTERA. 483 



but it has its mouth fitted for piercing and for sucking 

 blood. It annoys cattle greatly; and before storms and 

 in the autumn it enters our dwellings and attacks us. The 

 larvae live in fresh horse-manure. 



The Horn-fly, Hcsmatobia serrata (Haem-a-to'bi-a ser- 

 ra'ta). This is an exceedingly annoying pest of horned 

 cattle, which has spread over the United States in recent 

 years. It resembles the House-fly in appearance ; but is 

 less than half as large. These flies cluster in great numbers 

 around the base of the horns ; they also settle upon the 

 back. The larvae live in fresh cow-manure. 



The Screw-worm Fly, Campsomyia macellaria (Camp-so- 

 my'i-a mac-el-la'ri-a), is a bright metallic-green fly, with four 

 black stripes on the upper part of the thorax ; it measures 

 about one third of an inch in length. This terrible pest 

 resembles the flesh-flies in habits, and it deposits its eggs 

 in wounds, sores, and the nostrils and ears of men and 

 cattle. The larvae living in these situations often cause 

 serious sickness, and sometimes even death. 



The Blow-fly, CallipJiora vomitoria (Cal-liph'o-ra vom-i- 

 to'ri-a), is larger than the House-fly, and black in color, with 

 a steel-blue abdomen. It flies with a loud buzzing noise, 

 and lays its eggs upon meat, cheese, and other provisions. 

 The eggs hatch in about twenty-four hours, and the larvae 

 become full-grown in a few days. 



Subfamily ANTHOMYiiiSLE (An-tho-my-i-i'nae). 



The AntJiomyiids (An-tho-my 1 i-ids). 



The members of this subfamily differ from other Ca- 

 lyptrate Muscidae in having cell III 5 widely open, vein V I+ , 

 nearly straight (Fig. 589), and not bent in its outer part 

 towards the tip of vein III 4+6 , as in the preceding subfam- 

 ilies. In fact, the type of venation is the same as that 

 which is characteristic of nearly all of the Acalyptrate 

 Muscidae ; and as the alulets are quite small in some of the 

 Anthomyiids, it is difficult for the beginner to recognize all 



