DIP TER A. 
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, Hcematobia 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 recen-t 
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, Calliphora vomit or ia (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 ANTHOMYIIN7E (An-thomy-i-i'nae). 
The A nthomyiids (A n-iho-my'i-ids ). 
The members of this subfamily differ from other Ca- 
lyptrate Muscidae in having cell III 6 widely open, vein V 1+2 
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 
