340 



AN ECONOMIC ENTOMOLOGY. 



Imc. ^S'"^- 



on the jjrape, and not improbably other species occasionally 

 found in leaf-galls are predatory upon the original producer. As 

 a whole, the gall-midges are to be regarded as dangerous, and 

 the measures to be adopted against them are, in almost all im- 

 portant cases, modifications of farm practice, since they are usu- 

 ally beyond the reach of insecticide substances. 



This closes the series of long-horned, mosquito-like flies, none 

 of which are of direct benefit to the farmer, while not a few are 

 among his most dangerous foes. As a whole, the species should 

 be looked upon with suspicion and closely investigated when 

 they occur in numbers great enough to attract attention. 



Quite early in the season we may see large numbers of loose- 

 jointed, ungainly flies of moderate size, with long, stout legs, 

 heavy body, short, stout, though many-jointed antennae, and 



often, in the female, a ridic- 

 ulously small head. In 

 color they are black, or 

 black and yellow, or red. 

 These belong to the family 

 BibionidiS, sometimes 

 called " March-flies," from 

 their early appearance ; and 

 while their larvae are some- 

 times feeders on grass roots, 

 they ne\'er become eco- 

 nomically important. They 

 are mentioned here because 

 their early appearance in 

 great numbers sometimes at- 

 tracts attention. They are 

 often plentiful in orchards 

 just when the blossoms 

 open, but seem not to be 

 of any service in pollen- 

 izing. 



" Black flies," or "gnats," are in some localities serious pests 

 to man and domestic animals. The "black flies" of the North- 

 ern woods and the "buffalo-" and " turkey-gnats" of the South- 

 ern and Mississippi States are good examples. They are rather 



b 



Bibio alhit>ennis.—a, male; c, its head; b, W- 

 male ; rf, lier head ; e, f, g, other structural 

 details. 



