■^1-2 COXXECTICUT GEOL. AXD NAT. HIST. ST'IJVET [Bull. 



19. Halteres elongate, approximately one-half length of thorax or more 20 



Halteres short -- 



20. Male hypopygium with a single rostral spine ( Fig. 36, I ) spinifera 



Male hypopygium with two rostral spines 21 



21. General coloration dark brown, more or less pruinose, the praescutal stripes 



confluent ; male hypopygium with the rostral spines at base of prolonga- 

 tion ; basistyle with only a simple mesal lobe (Fig. 35, H) halterata 



General coloration yellowish brown, the praescutum with a broad dark 

 brown median stripe : male hypopygium with the subappressed rostral 

 spines placed beyond midlength of prolongation ; basistyle with complex 

 mesal outgrowths (Fig. 36, H) sphagnicola 



22. Wings with Rs short, subequal to basal section of Rt+r,; Sci some distance 



before origin of Rs (brcvivcna group ) 23 



Wings with Rs long, approximately twice the basal section of Ri+fi\ Sci 

 ending about opposite origin oi Rs 24 



23. Praescutum with three brown stripes, the median one subnitidous . . . .floridana 

 Praescutum opaque gray, the median region dark brown adirondacensis 



24. Apical cells of wing strongly infumed, especially in radial field; femora 



yellow, narrowly tipped with dark brown; male hypopygium (Fig. 36, E) 



profunda 

 Wings unicolorous, except for the stigma where this is present ; femora 

 dark, paler hasally 25 



25. Wings with stigma lacking or ill-defined ; male hypopygium with three to 



four rostral spines ; ventral dististyle and basistyle without supernumerary 



outgrowths (Fig. 35, C) ' ' distans 



Wings with stigma distinct ; male hypopygium with two rostral spines ; ven- 

 tral dististyle and basistyle witii complex outgrowths (Fig. 35, B) 



cramptoniana 



26. Scr ending some distance before origin of Rs, Rs and basal section of Rt+r, 



subequal ; male hypopygium (Fig. 35, A) brevivena 



Sc\ ending opposite origin of Rs or nearly so ; Rs conspicuously longer than 

 basal section of /?4+.-, 27 



27. General coloration of thorax clear gray 28 



General coloration of thorax brown or brownish black, at least on praescu- 

 tum ; pleura not clear gray 29 



28. Stigma of wing appearing as a narrow dark seam to vein Rl'. male hypo- 



pygium with caudal margin of tergite convexly rounded ; rostral spines 



from enlarged basal tubercles (Fig. 36, A) liberta 



Stigma of wing full, oval, of normal shape ; male hypopygium with caudal 

 margin of tergite deeply notched ; rostral spines not arising from enlarged 

 basal tubercles (Fig. 36, K) uliginosa 



29. Mesonotal praescutum with three confluent dark brown or black stripes ; 



antennae appearing moniliform, the flagellar segments subglobular to short- 

 oval ; male hypopygium with dorsal dististyle very slender, strongly arcu- 

 ated ; rostral prolongation beyond the spines slender, blackened (Fig. 36, J ) 



stulta 

 Mesonotal praescutum without such blackened confluent stripes ; antennae 

 normal, flagellar segments oval ; male hypopygium with the dorsal disti- 

 style broad, only slightly curved ; rostral prolongation beyond the spines 

 pale 30 



30. Male hypopygium with rostral prolongation stout, the two spines at mid- 



length (Fig. 35, G) haeretica 



Male hypopygium with rostral prolongation long and slender, the two spines 

 near base (Fig. 35, E) gibsoni 



Tlie following doubtful species are omitted from the key: 



L. (Dicraiwmyia) brevivenula Alex. (Philippine Journ. Sci., 40:247; 1929; new 

 name for L. (D.) flaz'cscens Dietz, preoccupied; Trans. Amer. Ent. Soc, 

 47: 239; 1921). 



Close to brcvivcna. Thorax dull yellow, with poorly indicated praescutal stripes, 

 the median one divided by a pale line. Rostrum dark yellow. Antennae entirely 



