THE INSECTS. 337 



them left their resting-places and commenced their peculiar 

 up-and-down motions, or dances in the air, the males pre- 

 dominating ; and when the females arrived these dances 

 greatly increased in rapidity, the union of the sexes taking 

 place at all hours during these movements. We have 

 often seen as many as six males attached to one female, 

 gradually descending to the surface of the water or the 

 ground before parting asunder, and in one instance we 

 found a male Danica in union with a female Vulgata, with 

 a male Vulgata clinging to the body. It appears to us, 

 from carefully observing numbers of males and females, 

 that in all probability a promiscuous intercourse between 

 the two (so-called) species is not uncommon. 



Our observations agree with Mr. Eaton's description of 

 the Ephemera danica, whether it be a distinct species or 

 a variety. We found both species in very considerable 

 numbers, the E. danica being more numerous. 



There were certain marks which we found pretty con- 

 stant. The spots on the anterior wings in the Danica were 

 as a rule five, one being close to the base of the wing. 

 In E. vulgata the spots were usually three, the abdomen 

 always as described by Eaton, the anterior segments being 

 ivory-white. 



The spot in the posterior wing absent in Danica, usually 

 present in Vulgata, particularly in the male. 



The males of both species much smaller than the females, 

 and appearing a day or two before the females. 



The sub-costal nervure, colour of the legs, and setae 

 varied considerably. 



The male May-fly in his perfect state is seldom a prey 

 to fish. He lives, when not resting under leaves, well 

 above the river, dancing in the air, waiting for his wives. 

 The swifts, swallows, chaffinches, and other birds are its 

 enemies at that period of its existence. But when the 

 duties are performed for which he has been brought into 

 existence, in a short time he falls helpless and dies, often 

 floating down the stream, then eagerly taken by the fish, 

 and in that condition known in angling parlance as the 

 spent gnat. 



