36 NORTH AMERICAN DIPTERA 



North America. No ke,ys are available for most of the groups in other 

 regions of the continent, with the exception of the papers listed in the 

 bibliography on certain groups of Tipulidae, which are lessened in 

 value due to the great additions that liave been made in later years. 



KEYS TO SUBFAMILIES AND TRIBES, GENERA, ETC. 



1. Terminal .segment of maxillary palpus elongate, whiplash-like; nasus 



usually distinct; antennae usually with 13 segments; wings with Sci 

 usually atrophied; vein Cu, constricted at m-cu, the latter usually 

 at or close to fork of M3+4 (1, 17 to 20); body-size usually large. 



(Tipulinas) ". " 2 



Terminal seg-ment of maxillary palpus short; no distinct nasus; an- 

 tennae usually with 14 or 16 segments; wings with Sci present, its 

 extreme tip atrophied in some Cylindrotomin^; vein Cui straight, 

 not constricted at m-cu, the latter placed far before the fork of 

 M3+4, usually at or close to fork of M (21 to 44); body-size 

 usually small or medium 19 



2. Legs unusually long and filiform; wings with vein Ri+j atrophied and 



with Sci ending in Sc close to origin of Rs (Dolichopeza, 19), 

 when Ri+! is preserved (Brachyprenina, 18; Tanypremna; Megis- 

 tocera, 17), vein Sc is very long, Sci reaching C as a distinct 

 element some distance beyond fork of Rs and with cell 2nd A usually 



very narrow (Dolichopezaria) 3 



Legs of normal stoutness for the family; wings with vein Ri+j pre- 

 served (20); when atrophied (a few species of Tipula) with Sc 

 of moderate length, Sc, atrophied before fork of Rs and Scj ending 

 at or near midlength of Rs (exception, some species of Longurio); 

 cell 2nd A of noiTnal width 8 



3. Wings with origin of vein Mi basad of that of M,+2; R2+3 angularly 



bent at near midlength (17); tropical, subtropical. 



Megistocera Wiedemann 

 Wings with origin of vein Mt distad of that of Mi+;, usually far be- 

 yond; R2+3 straight or nearly so, not angulated 4 



4. Wings with R,+2 pale, perpendicular to R2+3; Rs strongly arcuated at 



origin (18) Brachypremna Osten Sacken 



Wings with R1+2, when present, oblique; Rs straight or gently arcuated 

 throughout length, sometimes very short and transverse 5 



5. Rs of moderate length, subequal to m-cu; Sc long, Sc, preserved, 



ending beyond fork of Rs; R,+2 pale but preserved; tropical. 



Tanypremna Osten Sacken 

 Rs short, transverse, simulating a crossvein, about equal in length to 

 one-half m-cu; Sc unusually short, Sc, atrophied, Sc2 entering Sc 

 before to just beyond origin of Rs; R,+2 atrophied. (Dolichopeza) (I 



6. Wings with cell 1st M2 open by atrophy of basal section of Ms, the 



outer medial field thus appearing pectinately branched (19); 



temperate Dolichopeza: Dolichopeza Curtis 



Wings with cell 1st M2 closed 7 



7. Cells beyond cord with abundant macrotrichia; tropical. 



Dolichopeza: Megistomastix Alexander 

 Cells beyond cord glabrous; temperate. . . .Dolichopeza: Oropeza Needham 



