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 sweep-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 Oscinis 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-booklets; the 

 abdomen has fleshy protuberances for locomotion ; the 

 antennae are two-jointed. 



Aldrich has recently expressed the suspicion that the 

 genus Hippelates 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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