THE INSECTS. 331 



In the genus Ephemera are our May-flies proper. 



Mr. Eaton makes three species, Ephemera vulgata, 

 Ephemera danica, and Ephemera lineata, to which latter 

 he attaches the synonym Ephemera danica, Pictet. 



This genus has the following distinctive characters: 

 Eyes simple on both sides, always separated by a con- 

 siderable space ; wings, four, with numerous transverse 

 nervures ; the posterior (small) wings about the fourth size 

 of the anterior (large), having their nervation complete 

 and the costal border angular. The tarsae (terminal part 

 of the legs) five-jointed, of which the first is very short ; 

 the abdominal segments ten in number; the setae three, 

 generally equal in length. 



Stephens says that the eyes are rather large, ovate, 

 united on the crown in the males, somewhat remote in the 

 females ; hence the great number (sixteen) of his species 

 of this genus. 



More recent authors have removed insects with these 

 characters into other genera of the same family. 



Stephens wrote his work on the Mandibulata in 1833 \ 

 Pictet published his on the Neuropteres in 1843; the Rev. 

 A. E. Eaton's monograph appeared in I883. 1 



Mr. Eaton considers Ephemera danica to be the May-fly 

 of anglers, the female and male of the sub-imago (i.e., 

 as the insect emerges from the water) being respectively 

 designated by them as the Green Drake and the Bastard 

 Drake ; and he says that E. danica usually inhabits colder 

 and swifter waters than E. vulgata. 



Eaton differs somewhat from Pictet. We have placed 

 the descriptions of the two authors in juxtaposition for the 

 sake of comparison. 



The term sub-imago denotes that stage after the wings 

 are fully expanded, previous to the insect casting oft 



early in spring, and Mr. W. P. Crake records fish being caught 

 in April with their stomachs full of May-fly larvae, and also in 

 August. 



1 For a more extended and scientific account of the Ephemeridce, 

 we refer our readers to the Rev. A. E. Eaton's elaborate and exhaus- 

 tive monograph in the Transactions of the Linnean Society. 



