GEORGIAN BAY EPHEMERIDJE 123 



SESSIONAL PAPER No. 39b 



Nymph: 



Measurements: Body 10 mm.; setsB 6 mm. 



Slightly smaller than E. lutulenta, but very similar in colour, except that there 

 is a dorsal median longitudinal white stripe from the interior margin of pronotum 

 to the posterior margin of 10th abdominal segment. This stripe lies between the 

 double row of spines on the abdomen. Occipital tubercles slightly longer than 

 those of E. lutulenta. 



The nymphs of this species were not very abundant and were found in about 

 the same localities as E. lutulenta from June 3 to July 9. My bred specimens 

 are dated June 14th and June 15th. I was unsuccessful in rearing a male. 



^a 



Ephemerella bicolor Clemens.* 



,, , . (PI. XIV, Fig. 1). 



Male imago: ^ > o y 



Measurements: Body 5-6 mm.; wing 6mm.; setae 8-9; fore-leg 6. 



A small wholly brown species. It is very similar to E. lutulenta, in form and 

 structure and apparently there are no satisfactory characters by which to distin- 

 guish it, except its size. 



Female imago: slightly larger than male. 



Nymph: 



Measurements: Body 6-6* 5mm; setsB 3mm. 



These nymphs show a great variation in colour pattern. The light coloured 

 specimens are of a dirty white colour with brown markings. Head for the most 

 part brown, slightly paler towards posterior margin. Sides of pronotum brown; 

 anterior margin of mesonotum brown and a brown area at posterior margin be- 

 tween the wing pads. Anterior halves of abdominal segments 2 and 3 brown and 

 slight marks on 4th segment; brown areas on 6 and 7 about the median line, and 

 on segment 9, there are 2 small brown dots at anterior margin and a rather semi- 

 circular brown band posteriorly. Some specimens are almost entirely brown and 

 between these two extremes the amount of brown and white varies. A few speci- 

 mens, especially females, show a slight indication of tubercles but they are never 

 large as, in the preceding species. A double row of spines on abdominal segments 

 1-7. Posterolateral margin of 3-9 produced into broad flat spines. Gills on seg- 

 ments 4-7, covered by a large jointed elytra. Setae light brown basally, becoming 

 paler distally; well-fringed with hairs; joints brown. Legs rather small; femora 

 stout; colour for the most part brown, divided into 2 areas; the proximal one large 

 and contains a rectangular white spot; the distal one smaller and contains a per- 

 fectly round white dot. Tibiae brown at proximal end and a brown band near 

 distal end. Tarsi with a brown band toward proximal end; claws dark and 

 pectinated. 



The nymphs were everywhere abundant, especially along the open shore of 

 Station Island. I have them also from Rattlesnake Harbour, Gray Island, Giant's 

 Tomb Island, and Musquash River. The dates are from June 3 to July 9. Imagos 

 were captured and reared from July 1 to July 12th. 



*Clemens, *13, p. 336. 



