INSECTS INJURIOUS TO VEGETATION. 



fly from the effect it produces on horses. It lays its eggs in 

 dung, where its young are hatched, and pass through their 

 transformations. The larvas and pupae do not differ much in 

 appearance from those of common house-flies. 



The next three flies have feathered bristles on their antennae. 

 The first of them, a large, buzzing, and stinking meat-fly, 

 named Musca ( Calliphora) vomitoria, is of a blue-black color, 

 with a broad, dark blue, and hairy hind body. It is found all 

 summer about slaughter-houses, butchers' stalls, and pantries, 

 which it frequents for the purpose of laying its eggs on meat. 

 The eggs are commonly called fly-blows; they hatch in two or 

 three hours after they are laid, and the maggots produced from 

 them come to their growth in three or four days, after which 

 they creep away into some dark crevice, or burrow in the 

 ground, if they can get at it, turn to egg-shaped pupae, and 

 come out as flies, in a few days more ; or they remain un- 

 changed through the winter, if they have been hatched late 

 in the summer. A smaller fly, of a brilliant blae-green color, 

 with black legs, also lays its eggs on meat, but more often on 

 dead animals in the fields. It seems hardly to differ from the 

 Musca [Lucilia) Ccesar of Europe. The house-fly of this 

 country has been supposed to be the same as the European 

 Musca domestica; but I cannot satisfy myself on this point for 

 the want of specimens from Europe. It is possible that our 

 sharp-biting stable-flies, the meat-flies, and the house-fly, may 

 really be distinct species from those which are found in Europe. 

 Our house-fly is the Musca Harpijia^ or Harpy-fly, of my " Cat- 

 alogue." It begins to appear in houses in July, becomes ex- 

 ceedingly abundant in September, and does not disappear till 

 killed by cold weather. It is probable that, like the domestic 

 fly of Europe, it lays its eggs in dung, in which its larvae live, 

 and pass through their changes of form. The Americans are 

 accused of carelessness in regard to flies, and apparently with 

 some reason. But, if these filthy, dung-bred creatures swarm 

 in some houses, covering every article of food by day, and 

 absolutely blackening the walls by night, in others compara- 

 tively few are found; for tlie tidy housekeeper takes care not 

 to leave food of any kind standing about, uncovered, to entice 



