258 THE CANADIAN ENTOMOLOGIST 



25th; in the Muskosh Rapids from July 3rd to 5th, and at the 

 Chutes, July 24-29th. 

 Heptagenia luridipennis, Burm. 



Nymph. 



Measurements: Body 7-8.5 mm.; seta? 10-14. Head brown, 

 with light dots; anterior margin fringed with hairs. Prothorax 

 similar in colour to head ; on pronotum a light spot on each side of 

 median line; lateral to this another larger one, and lateral to this 

 another which extends to the lateral margin. Abdomen similar 

 in colour to prothorax; a row of black dots on each side correspond- 

 ing to the stigmal dots of imago; segment 3 for the most part light, 

 with a round brown spot in the median line and with two short 

 projections laterally; segment 4 with a small triangular brown spot 

 in median line with base to anterior margin, while apex meets a 

 large brown area, leaving a small light area on each side of triangle; 

 lateral to the brown area is a light one, and lateral to this again is 

 a triangular dark spot in the posterior angle of the segment; seg- 

 ment 5 much like the 4th ; segment 6 entirely dark, except for two 

 small spots at anterior margin and two toward lateral margin ; seg- 

 ment 7 with a triangular dark spot in median line, with base to 

 anterior margin and apex reaching about middle of segment; on 

 • each side of triangle two dark spots; segment 8 similar to the 6th; 

 segment 9 irregularly marked; roughly, it is dark, with a darker 

 median longitudinal line, two light spots on each side and another 

 at lateral margin; segment 10 entirely dark; ventrally there are 

 two dark spots at lateral margins of 9th segment, just beside the 

 lateral spines of that segment; sometimes a triangular spot in 

 median line also. Setae with basal half fringed with hairs. 



This was the last species to be taken. On August 23rd I found 

 them in a rapid just above Sandy Gray Falls, where the river flows 

 through a small gorge. I was successful in rearing quite a number 

 of images, dating from August 28th to September 1st. These are 

 slightly smaller than those Mr. Banks sent me and considerably 

 smaller than the measurements given in various descriptions. 



Heptagenia canadensis, Walker. 



Nymph. 



Measurements: Body 11 mm.; seta 15; antennae 3.5. Head 

 reddish brown in colour; a small dark area immediately in front of 



