268 



THE ZOOLOGIST. 



business to breed Mayflies for the express purpose of exporting 

 the larvae to ponds and streams from which the insect is 

 absent. It is stated that eight hundred thousand eggs were 

 obtained from one hundred and twenty females.* For the 

 successful rearing of the larvae running water is absolutely 

 essential. 



Ephemera danica, a slightly smaller species than E. vulgata, 

 appears about the same time as the latter, and according to 

 my experience is not a common insect ; neither does it occur in 

 anything like the abundance of that insect. The wings are 

 clear without markings, and shine with a beautiful iridescent 

 gleam. The caudal setae are very long, about twice the length 

 of head and body, and are two in number. The flight of 

 this insect is much swifter than E. vulgata, and it never 

 ascends to a very great height. The flight resembles that of a 

 dragonfly (Odonata). They frequent streams, and those with a 

 gravel and sandy bottom. I have frequently taken the male 

 insect a long distance from any water, and both sexes are fond 

 of settling in the middle of a road. The larva is of a dark 

 brown colour, and I have taken them about half an inch in 

 length. They become much paler, almost transparent, before 

 emergence. They have three caudal setae. 



At Frensham Great Pond, in South-west Surrey, on May 

 22nd, I found that thousands of the small Mayfly mentioned 

 previously (' Zoologist,' 1908, p. 458) had " hatched " out, and 

 left their pseudo-imago skins and nymph-pellicles on posts 

 about twenty yards from the water, and these were also thickly 

 intertwined among the herbage by the roadside in soft white 

 masses, which from a distance resembled the hairy fruit of the 

 willow. 



The nymph of this small fly, unlike that of E. vulgata, leaves 

 the water and climbs up a reedf to undergo its metamorphosis, 

 and finding their pellicles so far away from the pond was at first 

 astonishing until I realized what had happened, not thinking it 

 possible that the nymph could have crawled all that distance. 

 What had happened no doubt was what was witnessed by Reaumur. 



* ' Fishing Gazette,' May 22ud, 1909. 



f I found the reeds by the pond-side covered with nymph-pellicles like the 

 cast skin of a dragonfly larva. 



