GEORGIAN BAY EPHEMERIDM 117 



SESSIONAL PAPER No. 39b 



R. P. Wodehouse kindly gave me a number of specimens which he took at Shawan- 

 aga Bay, about fifteen miles north of Parry Sound on June 9 in 2 to 8 feet of water; 

 some from the south east shore of Manitoulin Island, June 26th, in water two to 

 five feet, and at Waubaushene on May 31 in 6 to 9 feet of water. Nymph sloughs 

 were taken at Go-Home Bay from June 24 to July 9. 



The first imago of this species was taken on June 5th at Giant's Tomb 

 Island, 4 miles south west of Station Island, but none were taken at Station Island 

 until June 21. After this date they became very abundant and remained so until 

 July 27th. The males occurred in fairly large swarms all along the shore. They 

 maintained their position in the air by a dancing motion, at a height of 10 to 35 

 feet. They appeared shortly before 8 'clock in the evening and continued until 

 dark. When a female appeared among them quite a commotion was noticed. 

 The successful male flying up beneath the female would grasp her around the 

 prothorax with his fore-legs, and, bending up his abdomen, would put his forceps 

 around her abdomen. His setae usually aided him in securing and maintaining 

 his hold, by being bent up over the female's body. The couple would then go off 

 on a gradual downward slant toward the water, before reaching which the male 

 would disengage himself and fly back to the swarm, while the female would fly 

 out over the water close to the surface and soon begin depositing her eggs, by 

 skimming the water with her abdomen. A peculiar thing was noticed, namely, 

 that the male Ephemera frequently attempted copulation with the male Hexagenia 

 evidently being deceived by the colour. 



Heptagenia. 



This proved to be a very abundant and interesting genus and is treated sepa- 

 rately elsewhere. The nymphs of eight species were taken and the imagos of all 

 of them reared, three of which proved to be new species. The life histories of none 

 of these have been previously described. Besides these eight, Mr. R. P. Wode- 

 house gave me several nymphs of another species which he discovered along the 

 east shore of Manitoulin Island, June 26th, 1912. These were not bred, so the 

 species has not been determined. 



Genus Ecdyiirus. 



Ecdyurus maculipennis Walsh. 



(PL XIII, Fig. 2). 



The nymphs were quite widely distributed, being common along open stony 

 shores and in rapids. They were taken as follows: 



(1) At Station Island, on July 2. 



(2) At Giant's Tomb Island on July 14, in a large stony bay commonly 

 called the "Gap," on the west side. 



(3) On August 19th at the South Watcher Island, 6 miles from the mainland. 

 This island is about 3 acres in extent and composed entirely of loose stones, with a 

 clump of small poplar, willow and alder trees in the centre, and was the breeding- 

 ground of hundreds of gulls. 



