48 NORTPI AMERICAN DIPTERxV 



72. A supernumerary crossvein in cell R3; eastern. 



Limnophila: Dicranophragma Osten Sacken 

 A supernumerary crossvein in cell M 73 



73. Rs long-spurred at origin; antennge of male elongate. 



Limnophila: Idioptera Macquart 

 Rs slightly if at all spurred at origin; antennae short in both sexes. 



Limnophila: Elaeophila Rondani 



74. Cell R3 sessile; cell M, lacking Limnophila: Idiolimnophila, subg. n. 



Cell R3 petiolate; cell Mi present 75 



75. Very large species (wing over 16 mm.); wings with the branches of 



M leaving the main stem at a strong angle, cell 1st M2 thus being 



strongly hexagonal; eastern Limnophila: Eutonia Van der Wulp 



Smaller species (wing under 14 mm.); wings with the branches of 

 M not strongly divergent, especially M3+4, cell 1st Mj being more 

 nearly rectangular in outline 76 



76. Wings with vein R2+3+4 short, subequal to the basal deflection of Rs; 



Rs elongate, exceeding four times R3+3+4; coloration polished black 

 or gray, the latter group having the male hypopygium with a series 

 of teeth on margin of outer dististyle, producing a comb-like ap- 

 pearance Limnophila: Prionolabis Osten Sacken 



Wings with R2+3+4 longer, usually exceeding the basal deflection of 

 Rr,; Rs shorter, not exceeding three times R2+3+4; where the above 

 characters are doubtful, the species have a closely iri-orate brown 

 wing-pattern; body coloration never polished black; when gray, 

 male hypopygium without a comb of spines on outer dististyle .... 77 



77. Rs short, weakly to more strongly angulated at origin, more rarely 



merely arcuated; R2+3+4 subequal to or shorter than m-cu; an- 

 tennae short in both sexes Limnophila: Phylidorea Bigot 



Rs longer, more gently arcuated; in species with shorter Rs, antennae 

 of male elongate and usually with R2+3+4 long, considerably exceed- 

 ing m-cu Limnophila: aberrant species 



ERIOPTERINI: SUBTRIBES, GENERA, SUBGENERA 



78. Nearly apterous, the wings reduced to microscopic structures that 



are smaller than the halteres; northern. (Claduraria) .Chionea Dalman 

 Fully-winged species 79 



79. Wings with cell Mi present SO 



Wings with cell Mi lacking (37-44) 84 



80. Antennae with the basal two to four segments united into a fusion- 



segment; wings with R2+3+4 much longer than the short basal section 

 of R:,; veins Sc, and R1+2 widely separated at margin, the distance 

 on Costa between them approximately three times r-m; legs plainly 



colored; temperate. (Claduraria) 81 



Antennae with all flagellar segments distinct; wings with basal sec- 

 tion of R5 elongate, much exceeding R2+3+4; veins Sci and R1+2 

 closely approximated at margin, the distance on costa between them 

 subequal to or shorter than r-m; legs conspicuously hairy, banded 

 with black, rufous and white; tropical. (Lecteriaria). 



Lecferia Osten Sacken 



