March, igio] . OSBURN : STUDIES ON SyRPHID^. 61 



in Bigot's collection under the name of Syrphus lapponicus from 

 North America." I believe that these four specimens referred to 

 belong to my S. pcrplcxiis* but cannot be certain without an examina- 

 tion of the specimens. At any rate, the presence of hairy-eyed and 

 bare-eyed species in both " Catahomha " and Syrphus effectually bars 

 this character from any use in establishing a separate genus. 



5. The third vein is curved in the " Catahomhas " above the first 

 posterior cell (PI. II, Fig. 8), but again we have species of the genus 

 Syrphus (arciiatiis Fallen (PI. II, Fig. 9) and anniilipes Zetterstedt) 

 which are fully as advanced in this respect as any " Catabomba," 

 while in " C" albomacnlatus the vein is but slightly bent. Assuredly 

 we can make no distinction on this basis. 



It is evident from the above that we cannot separate a genus 

 " Scccva " from Syrphus by even one constant character. Neither is 

 there a " distinct facies " presented by a combination of characters 

 of sufficient constancy to serve in the differentiation of such a genus, 

 since the facies is broken into on all sides by related species. The 

 result is that the species pyrasfri (Linne) with its var. unicolor 

 (Curtis), sclcnifjcus Meigen, albomaculatus Macquart and melanos- 

 toma Macquart must all be returned to the genus Syrphus. 



Certain systematists are inclined to view with regret the fact that 

 we have such large genera as SyrpJius, Erisfalis and others in which 

 the species may run into the hundreds. Such genera may exist, 

 however, and while the effort to discover absolute differences of 

 more than specific value is certainly laudable, the attempt to found 

 separate genera upon any other than well-marked characters which 

 show no intergradation can only end in greater confusion. The 

 very fact that we have such a large number of closely related species 

 covering a wide range of variability indicates a plasticity of the 

 genus which in itself should cause us to look with suspicion upon 

 new genera separated from the old one. On the other hand, we 

 may determine the existence of groups within the genus which, 

 while not necessarily constant, will serve every purpose for con- 

 venience of study without involving the synonymy or suggesting false 

 values in classification. 



* Studies on Syrphidae, Pt. I, p. 55. 



