Osten Sacken.] 138 [October 6, 



Analytical table of the species of Syrphus described in the present paper. 



A. Abdomen oval, with three principal crossbands, the second and 



third of which never interrupted. 



I. First crossband broadly and distinctly interrupted in 

 both sexes. 



a. Femora black at the base. 



aa. Antenna? brown, with more or less reddish 

 on the underside of the third joint; ab- 

 dominal crossbands distinctly attenuated 

 on both sides. 

 Eyes pubescent. 1 



1. S. torvus n. sp. 

 Eyes bare. 



2. S. rectus n. sp. male. 



bb. Antenna? uniformly black; abdominal cross- 

 bands straight, not attenuated at both ends. 



3. S. Lesueurii. 



b. Femora yellow at the base. 



2. S. rectus n. sp., female. 

 II. First crossband narrowly interrupted in the male; not 

 interrupted in the female. 

 a. Face yellow. 



4. S. abbreviatus. 

 Z>. Face with a brown stripe. 



5. S. amerieanus. 



B. Abdomen oval, the three principal crossbands broadly inter- 



rupted. 



I. Eyes distinctly pubescent. 



a. Abdominal spots straight; face without any large, 

 conspicuous black spot in the middle. 



6. S. contumax n. sp. 



1 The pubescence of the eyes is easily perceptible in male specimens ; in the fe- 

 males it is generally much rubbed off, and often almost imperceptible. Still, a 

 careful examination in an oblique light, especially of the lower half of the eye, 

 does not fail to reveal some traces of hairs, if there ever were any. Fortunately, 

 the females of S. torvus and rectus offer, in the coloring of their femora, a distinc- 

 tive character, which is much easier to perceive. Specimens subjected to such 

 investigations must not be too old; those kej>t f or years in a collection become 

 covered with a fine dust, which makes it very difficult to perceive whether the eyea 

 are hairy or glabrous. 



