356 AN ECOKOMIC ENTOMOLOGY. 



These flies are among the most effective of nature's checks to 

 caterpillars, especially cut-worms. 



The "flesh-flies" greatly resemble the Tachina flies in ap- 

 pearance, but the arista or bristle of the antennae is feathered 

 towards the base and is bare only at the tip. Some of these 

 species also are parasitic. Others have larvae that live in excre 

 mentitious material, in fruits, in meats, or in decaying animal or 

 vegetable matter generally. Such species usually produce their 

 young alive, or at least as eggs just ready to hatch, and the 

 majority are scavengers. None of the members of this family, so 

 iar as I am aware, are injurious, and they are always beneficial to 

 the extent, at least, of assisting in the removal of offensive matter, 

 animal or vegetable. 



The typical Muscids differ from the other species in this series 

 by lacking the spines of the thorax and abdomen, or having them 

 confined, in a very reduced state, to the tip of the abdomen only. 

 The arista or antennal bri.stle is feathered to the tip. The house- 

 fly is one of the best known of all insects the world over, and 

 there seems to be no region where it does not occur and is not 

 more or less annoying. It winters in our houses or out-buildings, 

 hiding in some sheltered spot in cellar or attic, or remaining 

 more or less active in our carefully warmed rooms. During the 

 early days of spring a few specimens make their appearance here 

 and there, sole survivors of the swarms of the preceding year. 

 These are mostly females ready to reproduce, and they lay their 

 eggs in any convenient pile of horse manure ; or, if that is not 

 available, in any decaying animal or vegetable matter. The 

 maggots hatch in a day or two, in a week or ten days are full- 

 grown, change to pupae, and in a very few days more a new 

 brood of flies is matured, already sufficient in numbers to become 

 more or less annoying. This process is repeated time and again 

 during the season, and the insects increase in numbers until after 

 midsummer, when they seem to lose activity to some extent, 

 although breeding until cold weather actually sets in. House- 

 flies are not injurious in any true sense of the word, although they 

 are distinctly annoying and may become dangerous by trans- 

 ferring disease germs from one point to another ; as when, after 

 alighting and feeding upon the sputum of a consumptive, they 

 tickle the nose of a healthy sleeper a few minutes thereafter. So 



