GEORGIAN BAY EPHEMERIDM 125 



SESSIONAL PAPER No. 39b 



apex extending almost to the anterior margin; from the anterior margin in the 

 median line, 2 bands arise, composed of black dots, which pass backwards curv- 

 ing outwards and ending near the base of the triangular brown area; between this 

 line and the triangular area is a light brown oval area; segments 7-10 almost en- 

 tirely blackish brown dorsally, but 7 and 8 have triangular white areas on sides, 

 and 9 a slight indication only; segment 10 has sides of dorsum white, ventrally 

 segment 1 dark brown; remainder white with brown markings; segment 2 has 

 2 brown spots, 3 with 2 smaller brown spots and a slightly reddish area at anterior 

 margin in median line; on 4 and 5 the brown spots become smaller and the reddish 

 area larger; segment 6 the reddish area is elongated to the posterior margin; 

 segments 7 and 8 have a median longitudinal brown line, thickened about the 

 middle, and 2 dots of unequal size on each side of it; segment 10 brown except for 

 a lateral white streak on each side. Forceps white; 4 jointed; setae white with 

 brown joints, minutely pubescent. Fore-legs brown; femur with a light area near 

 distal end, lateral to which is a dark brown band; tarsi with segments 1, 2 and 3 

 about equal in length, 4 slightly shorter, and 5 about half the length of 4. Hind 

 legs lighter in colour than fore; a brown band on femur is distal half; tibia with 

 a brown band about middle; tarsus light but brown at joints; joint between tibia 

 and tarsus 1 not distinct. Claws unlike. Wings with brown neuration; costal 

 cross-veins and others towards base of wing margined more or less with brown; 

 slightly clouded in apical costal area; a heavy brown cloud at bulla; often a small 

 cloud at bifurcation of median vein; cubitus 2 strongly bent at base. Hind wing 

 with a large brown cloud at base. 



Nymph: 



Measurements: Body 15 mm.; setae 5 mm. 



I have two of these graceful nymphs, a male and a female, both mature, but 

 imfortunately both died when just about to emerge. On this account it is difficult 

 to describe the colour pattern as the body of the subimago shows through the 

 nymph skin. 



Head vertical; body curved. Posterior lateral margins of abdominal seg- 

 ments 1-9 produced into spines. Dorsal colour pattern distinct on segments 9 and 

 10 only; 9th segment pale with a short brown median longitudinal stripe, commen- 

 cing at anterior margin; on each side of this is a short stripe of about the same 

 length, but placed more posteriorly; lateral to this again is a large brown area, 

 roughly triangular, apex at posterior margin, base at anterior; at lateral margin 

 slightly below middle line is a small brown spot; on 10th segment is a median brown 

 longitudinal stripe with 2 dots on each side of it. Ventral surface of abdomen 

 white with 3 longitudinal brown stripes, one median and 2 lateral. Gills on seg- 

 ments 1-7; double on 1, 2 and 3. Three setse of equal length; lateral ones 

 fringed with hair on inner margins only except towards tips; in these specimens 

 the lateral setse are brown, lighter towards tips, while the median one is whitish; 

 setse banded toward distal end with brown. Legs pale; femur with proximal end 

 brown and a brown band beyond middle; tibia with a brown band about the 

 middle; tarsus with brown band towards proximal end; fore tarsus much longer 



