XLV. Family OSCINID^E. 



Small, bare species. Head usually hemispherical; face 

 usually nearly vertical in profile; oral border rarely with 

 vibrissae; front broad, flattened, sometimes with bristles. 

 Antennae usually short and the third joint rounded. Gen- 

 italia hidden. Wings moderately or very short; auxil- 

 iary vein vestigial; posterior basal cell united with discal 

 cell; posterior cross-vein sometimes wanting; anal cell 

 vestigial or wholly absent. Legs short; femora rarely 

 thickened; tibiae without preapical bristle. 



This family of flies is always sure to be represented by 

 numerous specimens and species in any collection of dip- 

 tera. The flies are very common, and are collected in 

 large numbers by the sw r eep-net from rank growing grass 

 and over meadow-lands. Most characteristic of the fan - 

 ily is the absence of auxiliary vein and the posterior 

 basal and anal cells, in these respects, however, agree- 

 ing with the Ephydridae, from which they will usually 

 be distinguished by their lighter colors — the Ephydrids 

 are almost invariably black, — the smaller mouth, the 

 usually bare arista, the occasional presence of oral vibris- 

 sae, etc. 



The larvae of several species of Osctnis have been bred 

 from wheat, oats, rye and grass stems, and Phragmites; 

 the larvae of Siphonella from Cirsium, etc. The larvae 

 are thick, cylindrical, with stout mouth-hooklets; the 

 abdomen has fleshy protuberances for locomotion ; the 

 antennas are two-jointed. 



Aldrich has recently expressed the suspicion that the 

 genus I appelates is not well founded, and I am inclined 

 to agree with him. While the presence of a booklet at 

 the tip of the hind tibiae would seem decisive, yet its 



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