1931 ] 
Notes on the Genus Ephemerella 
27 
SOME PRELIMINARY NOTES ON THE GENUS 
EPHEMERELLA 
By Anne Louise Steger 
Cornell University, Ithaca, N. Y. 
In an attempt to fill in some of the gaps left by Miss 
Anna H. Morgan in her study of the Mayflies of Fall 
Creek in 1911 (Ann. Ent. Soc. Am. 4:98-119), some rear- 
ing and collecting work was carried on during the summer 
of 1930 at Cornell University under the direction of Dr. 
Needham with the genus Ephemerella. As a result I was 
able to obtain stages of several of the local species which 
had not as yet been taken or described. Following is a 
table of the local species taken, indicating those stages 
which had already been described ( D ) and those which 
had not, and which were collected last summer (U) : 
Species Nymph Subimago Imago 
$2 S 2 
E. cornuta D D U U U 
E. deficiens D D D D D 
E. dorothea D U U D D 
E. rotunda D U D U D 
E. septentrionalis U U U D U 
The rearing of the nymphs to the subimago and imago 
stages was carried on in a deserted pump house on Beebe 
Lake, where it was possible to have a constant supply of 
fresh water running through the troughs. The nymphs 
were collected in streams by means of a small wire hand 
screen, brought home and put into wire cages in the 
troughs, after having been properly identified and sepa- 
rated according to species. The cages were labelled with 
