244 NEW YORK STATE MUSEUM 



mind in using this key, that I have seen but few species save those 

 mentioned in my Hst or figured in the plates, and other species may 

 exhibit characters different from those I attribute to the genus. 

 Notwithstanding this, the things found in the species I have seen 

 should be suggestive, and should add something to the final work- 

 ing out of the system for this group. It is certain that a thorough- 

 going study of the antennae, the mouth parts, the legs, or the 

 appendages of the abdomen would likewise yield valuable results, 

 also, the study of the immature stages, for which I am endeavoring 

 to gather material for future use. 



Key to the North American genera of crane iiics 



(Based on venational characters) 

 a Rs four branched, the posterior fork more deeply branched or, if but 

 three branched, it is R' and R'^ that are fused. A single anal 



vein • PTYCHOPTERIDAE 



b Rs four branched, M three branched cord deeply indented by first fork 



of M ; 5"c2 and cross vein ?n present ; Idioplasta only. .TAN YDERINAE 



bb Rs three branched ; AP two branched ; cord not indented by the median 



fork, Sc2 and cross vein m absent PTYCHOPTERINAE 



c M two branched Ptychoptera 



cc M one branched Bittacomorpha 



aa Rs never four branched; when three branched it is Rt, and Ri that have 

 fused (for a few apparent exceptions, all of which have the forks of 

 nearly equal length, see p. ante). Two anal veins present (three in 



the fossil Cladoneura) TIPULIDAE 



b Scx wanting: R^ directed forward and reduced, or wanting: basal de- 

 flection of Cmi never extensively fused with ilfa TIPULINAE'^ 



bb Sci usually present and joining the costa beyond Sc2, which often 

 recedes toward the wing base: sometimes both tips are wanting. 

 Cui usually extensively fused with M3 at its basal deflection, the cross 



vein in ni-cu being eliminated thereby LIMNOBIINAE 



c Ri, R2 and R3 extensively fused together from the tips backward in 

 a long, straight vein ; M skewed forward at its first fork, its base 

 being in line with the tip of Cu. Tips of Sc often rudimentary. 

 Cross vein m never atrophied: Cylindrotomini 



d Ml and M2 separate at tips Cylindrotoma 



dd Ml and M2 fused to the wing margin 

 e Cross vein m present 



f Antennal joints subcjdindric Liogma 



ff Antennal joints subglobular Triogma" 



ee Cross vein in eliminated by fusion of adjacent veins. Phalacrocera 

 cc Ri, Ri and R^ not all fused together into a long, straight tip 

 d Rs three branched 



a I am not sufficiently acquainted with the genera of this family to attempt a venational 

 key for them. I know only those genera figured herewith and Tipula and Paphyrhina , 

 Antennal characters seem to have furnished.the basis forjmo^t of the genej-a. 



l> Triogma I have not seen. 



