GEORGIAN BAY EPHEMERID^ I 41 



SESSIONAL PAPER No. 39b 



between each lateral ocellus and eye. Another lateral to each eye along margin of 

 head; mouth parts of the type belonging to group 2. 



Pronotum reddish brown with a dark and an approximate light area in each 

 lateral half; margin colourless. 



Abdomen darker than thorax; each segment with four light longitudinal 

 streaks, 2 near median line and the other two near lateral margin ; black dots, 

 corresponding to the stigmal dots just inside of lateral light streaks. Ventrally the 

 abdomen is almost white, each segment has two light brown lateral streaks, while 

 9th has its lateral and posterior margins margined with light brown. Short lateral 

 spines at posterior lateral angles of segments 8 and 9. Setae of equal length; 

 light brown; joints fringed with hair. Gills oval and pointed, femur of fore-leg 

 light brown with 4 light areas. Two small ones towards anterior margin and two 

 large towards posterior. Distal end light coloured. Femora of hind legs with 

 fewer pale-markings. Tibae alternately banded with brown and white. Tarsi 

 have very broad median bands, legs slightly hairy along posterior margin. 



This species was the second most abundant at Go Home Bay. The nymphs 

 were taken from May 25th to June 31st in various localities, but never in swift 

 water, the usual place being quiet bays. On Sept, 5th some small nymphs were 

 found in a small creek which were evidently the next generation. 



Almost mature nymphs were taken in this creek on May 31. The first bred 

 specimen is dated June 1, and the last July 4th. Imagos were very abundant at 

 Station Island from June 25th to July 15th. 



Heptagenia frontalis Banks. 



,, , . (PI. XVI, Fig. 3). 



Male imago: ^ j b ^ 



Measurements: Body 7-8 mm.; wings 9 mm.; setas 18-20 mm.; forelegs 7 mm. 



Much like H. canadensis but lighter in colour, face yellowish a black dot on 

 face below each antenna; a smaller black dot near inner margin of eye; pronotum 

 light brown with a black streak on each side. Mesonotum rich brown; sides of 

 thorax whitish yellow, segments 1-7 of abdomen very light, with posterior margin 

 black; 8-10 reddish dorsally; stigmal dots distinct; setse white. No dash in wing 

 and cross veins not margined. Femora yellowish with black median and apical 

 bands. 



Female imago: 



Measurements: Body 8-9 mm.; wings 10 mm.; setse 15 mm. 



Head and thorax light yellow ; dots on face beneath antennae almost forming 

 bands; sometimes a black dot at lateral margin of each side of pronotum, usually 

 a few cross-veins margined with black on the wing. 



Nymph: 



Measurements: Body 9-10 mm.; setse 9-10 mm. 



Head yellowish brown in colour; three almost round light spots along anterior 

 margin of head; a light area in front of each ocellus; usually a light area along 

 median line between eyes and 2 smaller ones lateral to this along posterior margin 



