INSECUTOR INSClTm MENSTRUUS 91 



CRITICAL NOTES ON SYRPHID^ 



By FREDERICK KNAB 



Baccha cylindrica Fabr. 



Syrphus cylindricus Fabricus, 1781, Spec. Ins, vol. 2, p. 429. 



Baccha cylindrica Fabricius, 1805, Syst. Antliat., p. 199. 



Baccha cylindrica Wiedemann, 1830, Aussereurop. zweifl. Ins., vol. 



2, p. 92. 

 Ocyptamus conformis Loew, 1866, Berlin. Ent. Zeitschr., vol. 10, 



p. 38. 

 Ocyptamus fascipennis V. d. Wulp (not Wiedemann, not Mac- 

 quart), 1883, Tijdschr. v. Ent., vol. 26, p. 9. 

 Ocyptamus conformis v. Roeder, 1885, Stettin. Ent. Zeit., vol. 



46, p. 342. 

 Baccha fuscipennis Williston (in part, not Say), 18S6, Synopsis 



No. Amer. Syrph., p. 119. 

 Ocyptamus fuscipennis Townsend (not Say), 1895, Trans. Amer. 

 Ent. See, vol. 22, p. 39. 

 The synonymy above indicated shows that the status of this 

 species is not clearly established. It is evident from the litera- 

 ture that Baccha cylindrica was not clearly differentiated from 

 B. fuscipennis, recent authors considering them as conspecific. 

 They are, however, abundantly distinct, although this is not 

 apparent from the wing-pattern, the feature which has chiefly 

 engaged systematists. The identity of the Fabrician species 

 seems to have been neither suspected nor investigated, although 

 Wiedemann gives an excellent description from the type. 



Baccha cylindrica has the wings extensively deep blackish 

 brown ; there is a large purely hyaline spot apically, bounded 

 anteriorly by the third vein and occupying the distal half of 

 the subapical cell and the parts beyond ; there is a large hyaline 

 streak in the discal cell and a smaller clear spot at the distal 

 end of the second basal cell ; the axillary area is wholly clear. 

 The face is wholly pale yellow, this color extending upward 

 at the sides of the frons in long triangles. The third antennal 

 joint is wholly black. The abdomen is steely blue, moderately 

 shining, the second, third, and fourth segments with broad 

 velvet-black bands, somewhat broader and more remote from 

 hind margins than in fuscipennis, that on the fourth segment 



