FAMILY SYRPHID.E THE FLOWER FLIES 259 



51. Third antennal segment elongate; apical crossvein more or less recur- 



rent (2, 3, 50) Orthoneura Macquart 



Third antennal segment never twice as long as wide 52 



52. Disc of abdomen opaque black, the sides shining (4, 52, 92, 102). 



Chrysogaster Meigen 

 Disc of abdomen either wholly shining or with shining spots or bands. 63 



53. Abdomen constricted basally or the third antennal segment very large 54 

 Abdomen broad; third antennal segment of normal size 57 



54. Antennse with a terminal arista on the produced upper angle (103). 



Pelecocera Meigen 

 Antennae with dorsal arista, the third antennal segment not produced 

 at point of its insertion 55 



55. Abdomen not constricted basally Chamaesyrphus Mik 



Abdomen petiolate 56 



56. Third antennal segment longer than wide; arista shorter than an- 



tennae (93, 106) *Neoascia Williston 



Third segment at most slightly longer than wide, the arista longer 

 than antenna (94, 105) fSphegina Meigen 



57. Face wholly black in ground color 58 



Face partly yellow in ground color 61 



58. Hair of the thorax and abdomen scale-like and appressed. 



Lepidostola Williston 

 Pile not scale-like, much of it erect 59 



59. Scutellum large, subquadrate; male dichoptic 60 



Scutellum rounded apically; male holoptic (107) Myiolepta Newman 



60. Mesonotum with a large, flattened rectangle posteriorly (58, 61). 



Chalcosyrphus Curran 

 Mesonotum regularly convex (62, 108, 109) Chalcomyia Williston 



61. Pile mostly scale-like and closely appressed (27, 124, 125). 



JEumyiolepta Shannon 

 Pile normal 62 



62. Legs bearing distinct bristles (96, 113) Hammerschmidtia Schummel 



Legs without bristles 63 



63. Epistoma produced into a long, porrect snout (95, 112) . .Rhingia Scopoli 

 Epistoma not produced snout-like 64 



64. Tlie costal vein ends at the tip of the wing (55, 56, 57, 97, 111). 



§Brachyopa Meigen 

 The costal vein ends before the tip of the wing (60, 63, 64). 



TJCynorhina Williston 



* Curran, 1925, Pr. Ent. Soc. Wash., xxvii, p. 51. 



t Shannon, 1923, Bull. Brooklyn Ent. Soc. xviii, p. 19. 



t Malloch, 1922, Ent. News, xxxiii, p. 267. 



§ Curran, 1922, Ann. Ent. Soc. Amer., xv, p. 243. 



1 Curran, 1924. Can. Ent., Ivi, p. 195. 



