THE SYRPHIDAE OF OHIO 77 



40. Eyes of male with an area of enlarged facets above; fourth segment of abdon;en 



with two median yellow stripes and oblique side spots (Fig. 64) Allograpta 



(P- 87) 



Eyes of male not with an area of enlarged facets above; fourth abdominal seg- 

 ment not so marked 41 



41. Face projecting below; slender species, the hypopygium often large (Fig. 71 ) 



Sphaerophoria ( p. 88) 



Face receding; abdomen oval Xanthogramma (p. 87) 



42. Thickly pilose species; the abdomen black, the basal part light yellow. Leucozona 

 Thinly pilose species; abdomen not so marked 43 



43. Hind femora thickened 44 



Hind femora slender 47 



44. Species wholly or chiefly reddish or lutescent 46 



Black species, sometimes with luteous spots on face, humeri and basal angles of 



abdomen 45 



45. Scutellum unusually large, nearly square in outline (Fig. 203); males dichoptic 



Chalcomyia (p. 83 ) 



Scutellum oval ; males holoptic Myiolepta ( p. 83 ) 



46. Face carinate; abdomen oval . Brachyopa (p. 89) 



Face tuberculate; abdomen more elongate Hammerschmidtia 



47. Epistoma produced into a long porrect snout (Fig. 227) Rhingia [p. 89) 



Epistoma not produced (compare Paragns sp. if small) facial orbits limited by a 



slender groove (Fig. 220) Chilosia (p 82) 



48. Third vein bent deeply into the first posterior cell (Fig. 231 ) 51 



Third vein not bent deeply into first posterior cell; third antennal joint elongate 

 ( Fig. 222 ) 49 



49. Arista very densely- plumose, appearing as a solid mass, the arista itself also thick- 



ened Copestylum 



Arista feathery plumose (Fig. 222) 50 



50. Hairs of arista retrorse; males dichoptic Megametapon 



Hairs of arista not retrorse; males holoptic Volucella (p. 89) 



51. Hind femora with a sharp tooth-like projection below near distal end (Fig. 237); 



sixth vein beyond anal cell strongly curved; large species Milesia (p. 97) 



Hind femora without such tooth . 52 



52. Frontal triangle of male strougl}- protuberant; rather large, dark colored species 



( Prioiiienis, Doliosyrphus) Eristalis (p. 90) 



Frontal triangle not protuberant J3 



53. Epistoma produced into a long porrect snout Licastrirhyncha 



Epistoma not produced 54 



54. Thorax wiih distinct yellow markings, hind femora thickened; hypopygium en- 



larged Meromacrus (p. 92) 



Thorax not with distinct yellow markings, sometimes wh it e-fasci ate; femora some 

 times thickened; hypopygium not coni-picuously prominent. . . .Eristalis (p. 90) 



55. Arista plumose ( Fig. 222) 5^ 



Arista bare or pubescent ( Fig. 24 r , 22 1 ) 60 



56. Antennae elongate, the third joint more than twice as long as wide [Pha/acro- 



III via, aiaiirotriclia) (Fig. 222) Volucella (p. 89) 



