THE MARCH-FLIES 



(Family Bibionidce.) 



The flies of this family are not especially interesting. They 

 are of medium size and are rather thick-bodied and rather hairy 

 but are weak fliers. Their wings are frequently smoky. Some 

 species, as Scatopse, are very small. There seems to be nothing 

 especially interesting about the group, although more than three 

 hundred species are known. 

 The larvae are cylindrical and 

 have transverse rows of 

 bristles and the head, which 

 is rarely obvious in dipterous 

 larvae, shows eyes. They feed 

 upon excremental or vegetable 

 substances and are said to 

 attack the roots of growing 

 grass. One of our commonest 

 species is Bibio albipennis. 

 This species sometimes occurs 

 in enormous numbers. In the 

 spring of 1891, according to 

 Osborn, it abounded in parts 

 of Iowa and was erroneously 

 reported as doing much dam- 

 age to vegetation. In this 

 form the wings are white, 

 quite contrary to the general rule in the family. Other species 

 are of a deep red color with dark wings. The larvae of some 

 species of this family have been found on the surface of snow. 

 The flies of the genus Scatopse breed in decaying vegetable 

 material, in sewers, and in human excreta. Scatopse pulicaria is 

 common on our windows at certain seasons of the year and, as 

 it is an excrement fly, is a dangerous inhabitant of houses. 



119 



Fig. 68. — Bibio albipennis. 

 (After Lintner.) 



