124 MARINE AND FISHERIES 



^ 5 GEORGE v., A. 1915 



Genus Drunella. 



I have two nymphs of this genus, identified for me by Dr. Morgan, but as I 

 have not reared any images, I think it advisable not to describe the nymphs at 

 the present time. 



Caenis diminuta Walker. 



This little nocturnal species came to the lamp in the reading room for the first 

 time on July 2, and was taken as late as August 12th. 



The nymphs are quite abundant in shallow, almost stagnant pools and la- 

 goons from June 5 to July 30. I have them from various places around Georgian 

 Bay. 



% 



Tricor3rthus allectus Needham. 



The nymph was dredged up from a slightly sandy bottom in water 5 to 15 

 feet deep on Sept. 3. They were not reared, but imagos were taken July 3 and 9. 



Chirotenetes albomanicatus Needham. 



On June 161 found a nymph slough at Sandy Gray Falls on the Go Home River 

 but was unable to find either nymphs or imagos. I did not get up to the falls again 

 until August 23 and then found the numerous small nymphs of the next generation. 



Siphlurus flexus Clemens.* 



Two beautiful Siphlurus nymphs were taken early in the season but both died 

 before time of emergence. The first was found May 25th in the bottom of a canoe 

 when some water was being emptied from it. The other was found June 3 beneath 

 a stone in about one and a half feet of water along the open exposed shore of Sta- 

 tion Island. Quite a number of imagos, apparently Siphlurus, were captured about 

 this time and it seemed quite probable that they were the same species as the 

 nymphs; and I think I have proved this quite conclusively by the wing venation. 

 The wing of the imago has a very characteristic bend in Cubitus 2 at the base and 

 the wing pad of the nymph shows this bend very distinctly. Again, thfe imago 

 apparently has claws like an Ameletus, the two on one leg being unlike, and this 

 can be made out in one nymph distinctly, due to the nymph dying just when about 

 to emerge. 

 Male imago: 



Measurements: Body 13-14 mm.; wing 12-13; setse 23-24; fore-leg 12-13. 



Head blackish brown except lower part of face, which is hyaline, tinged with 

 brown; eyes large, meeting dorsally. Notum blackish brown. Sides of thorax 

 marked irregularly with white. Abdominal segments 1, 8, 9 and 10 dark, seg- 

 ments 2-6 lighter in colour; these are light toward anterior margin and brown toward 

 posterior; in the median line the brown is dark and forms a triangular area, the 



♦Clemens, '13, p. 338. 



