THE CANADIAN ENTOMOLOGIST. 197 



NOTES ON OUR EASTERN SPECIES OF THE MAY-FLY 



GENUS HEPTAGENIA. 



BY NATHAN BANKS, EAST FALLS CHURCH, VA. 



The May-fly genus Heptagenia is a very well marked one, in the 

 form that Walsh used the name. Eaton split up the genus into several, 

 none of which are readily identified ; most of these genera are based on 

 secondary sexual characters, which I cannot recognize as of generic value. 

 Epeorus (with Iron) is perhaps the most distinct group, and may yet be 

 used in a subgeneric sense, if some character can be discovered to support 

 it. In the male the basal joint of tarsus I is subequal to the second joint, 

 and in most of the species the setse are brown, not marked with black at 

 tips of joints ; however, in H. (Epeorus) modesties^ described below, the 

 setse are as in other Heptagetiice. 



It may be remarked here that in Heptagenia every alternate joint of 

 the setae is unmarked or only faintly marked at its tip ; whereas in 

 Siphloniirus every joint of the selJfi is equally marked with black at its 

 tip ; this enables one to readily distinguish the setse of these two genera, 

 when, as frequently happens, they are broken off in a vial or box contain- 

 ing both genera. 



I have added the description of one Californian species of Epeorus. 



The following table of the Eastern species of Heptagenia (except 

 Epeorus) applies to the males ; females, however, will, in some cases, 

 also run out correctly. There are several species described from the 

 Eastern United States or Canada that I have not identified ; and one or 

 two of my identifications are somewhat doubtful to me, especially H. 

 simplex. The form I have from Washington may very possibly be a new 

 species allied to the true H. sitnplex. 



1. Thorax with a broad dark median stripe, or two narrow stripes close 



together, male with basal joint of tarsus I longer than apical 



joint H. verticis. 



Thorax without dark median stripe 2. 



2. Tips of hind wings distinctly dark ; beneath the bulla the cross-veins 



are more numerous than elsewhere and faintly clouded. Z^. vicarius. 

 Tips of hind wings not darker 3. 



3. Anterior margin of head black ; colour pale yellowish, with black spots 



on the pronotum and pleura, no dash in wings H. niarginalis. 



Anterior margin of head not black, though there may be black spots 

 above it , , 4. 



June, 1910 



