l8o NEW YORK STATE MUSEUM 



and yet differing considerably in structural characters. The third 

 vein as a rule joins the margin of the wing beyond the apex. We 

 have referred to this group a considerable number of forms having a 

 more or less uniform structure and not referable to such recently 

 erected genera as Karschomyia, Lobodiplosis, Youngomyia and 

 Coquillettomyia, all of which are separated from this large genus 

 by well-marked structural characters. 



Key to Species 



a Third vein uniting with costa well before the apex 

 b Harpes indistinct, not lobehke 



c Length .75 mm, abdomen pale yellowish, the distal stem of the 

 fifth antennal segment with a length twice its diameter, the fourth 



palpal segment one-fourth longer than the third 



r e d u c t a Felt, C. 479 



cc Length i mm, abdomen pale yellowish, the distal portion of the 



stem of the fifth antennal segment with a length two and one-half 



times its diameter, the fourth palpal segment one-half longer than 



the third. Reared probably from red spiders 



i n s u 1 a r i s C. a24i3 

 aa Third vein uniting with costa beyond the apex 



b Ventral plate long, at least two-thirds the length of the style 



c Ventral plate expanded apically, broadly and deeply emarginate 

 d Dorsal plate long 



e Lobes greatly expanded distally, spatulate; abdomen yel- 

 lowish, length .75 mm angulata Felt, C. 332a 



ee Lobes long, not greatly expanded laterally, narrowly 

 rounded apically 

 / Abdomen yellowish brown, reddish brown basally, 

 length .75 mm, the fifth antennal segment having the 

 stems two and two and one-half times their diam- 

 eters, respectively; bred from folded, thickened cherry 



leaves cerasifolia Felt, C. ai57i 



// Abdomen light yellowish, reddish basally, length i mm; 

 fifth antennal segment having the stems two and 

 one-half and four times their diameters, respectively; 



bred from globular leaf gall on poplar 



p o p u 1 i f o 1 i a Felt, C. ai5i4 

 /// Abdomen pale yellowish, orange-tinted basally; length 

 1.5 mm, fifth antennal segment with the stems three 

 and four times the length of their diameters, respec- 

 tively; bred from fungus on Impatiens, Oecidium 



impatientis impatientis Felt, C. ai542 



dd Dorsal plate short, broad, the lobes broadly rounded and 

 margined with setae; ventral plate deeply and triangularly 

 emarginate, the lobes slender, the basal portion of the stem 

 of the fifth antennal segment with a length two and one-half 

 times its diameter r o t u n d a t a Felt, C. 634, 704, 564 



