1920] Melander: Nearctic Tetanoceridce 323 



Limnia Dcsvoidy. 



Limnia Desvoidy, Myod. 684 (1830). 



Oregocera Rondani, Prodr. Dipt. Ital. I. 106 (1856), VII, Sciom. 23 (1868). 



The brown costal margin distinctly interrupted by clear spots; eyes 

 round; arista loosely plumose, third antennal joint but slightly excised 

 above. (Boscii Desvoidy) 2 



The uninterrupted brown costal border attaining apex of the wings; eyes 

 horizontally oval; arista closely plumose to tip, third antennal joint 

 distinctly excised above 3 



2. Brown spots of wings paired so as to form transverse double bands, 



interspaces vellow. Me., Mass.,* Ct., Ont., Queb., N Y Pa N J 

 Md., Va., N. Car., Mid. States, 111.,* Wise.,* Col., Mont. (T. com- 



binata Loew). {Tetanocera) Boscii Desvoidy, s. str. 



Wing reticulation uniform, not forming cross-bands, interspaces hyaline. 

 Me., N. H., Queb., Ont.,* N. Y., N. J., Mid. States, Mont.,* Wash.* 

 (r. mopa Adams). {Tetanocera) Boscii var. sparsa Loew 



3. Robust species, 7 to 8 mm. in length; second antennal joint much longer 



than third and strongly bristly above. Id.,* Wash.,* Or.,* Cal. {Teta- 

 nocera) pubescens Day 



Length 4 to 7 mm.; second antennal joint not much longer than third and 

 not remarkably setose above, usually only bisetose 4 



4. Second antennal joint with distinct- dark spot, third joint short and 



blunt; frontal bristles weak; costal margin dark, with small round 

 spots in marginal and submarginal cells; scutellum yellow. Md. 



(Cresson, 78) shannoni Cresson 



Antennae not maculate, third joint more acute; frontal bristles strong; 

 scutellum often darker 5 



5. Posterior crossvein nearly straight and perpendicular; prescutellar 



bristles vestigial or wanting. {costalis Loew) 6 



Posterior crossvein distinctly sinuous; prescutellar bristles more or less 

 developed ^ 



6. Scutellum uniformly yellow, contrasting with the mesonotum. notal 



vittae faint; submarginal cell with elongate dark spots along the second 

 vein, the median streaks almost obliterated. N. H., N. Y., Md., 111. 



var. costalis Loew, s. str. 

 Scutellum not contrasting with mesonotum; dark spots of submarginal 

 cell usually short, median streaks usually evident 7 



7. Brown of costal margin continuing unbroken to or beyond fourth vein; 



mesonotal vittae strong, distinct brown vittae present between the 

 narrow median yellowish stripe and the lateral gray vitta;; hvpopj'gial 

 paramera square and bare, with prong at middle of apical edge'. Mont.,* 



Id.,* Wash.* costalis var. vittata, n. var. 



Brown of costal margin stopping at third vein; mesonotal vittffi faint. 

 Avon, Id.,* 26 July, 1912 costalis, var. brevicostalis, n. var. 



8. Notal setulae abundant, about 4 irregular rows on the central vitta; cheeks 



less than half the eye-height; pubescence of arista longer and more 



open; front wider than long 9 



Notal setulas sparse, about 2 rows on the central stripe; cheeks more 

 than half the eye-height; pubescence of arista short and close, almost 

 appressed; sides of interfrontal stripe parallel; some pale spots touching 

 second vein, about 14 pale spots in first posterior cell; dark spot at 

 posterior fronto-orbital weak; lower pleurae with yellow tinge, {sara- 

 togensis Fitch ) 1 1 



