180 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 lobelike 
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................ 
redweta Pelty Graze 
cc Length 1 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............1....-- 
insularis C. a2413 
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 
f 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... ..... <cerasifo lina, RelivGyannz. 
ff Abdomen iene eller, reddish basally, length 1 mm; 
fifth antennal segment having the stems two and 
one-half and four times their diameters, respectively; 
bred from globular leaf gall on poplar.............. 
populifolia Felt, C. ar514 
fff 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. a1542 
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... .. rotundata Felt, C. 634, 704, 564 
