EPHEMERAE. 55 



There are various species of Ephemera, differing in size and 

 colour but similar in habits and economy. Of these, one kind* 

 is distinguished by having only two tail-like appendages in- 

 stead of three. But besides these Ephemera, properly called 

 May-flies, the same appellation is often given by anglers to 

 another tribe of insects, perfectly distinct, known also as Caddis 

 or Case-flies, which only resemble the Ephemera in passing 

 their early stages under water, and in serving as the staple 

 food of fish and swallows* 



The seasons as well as hours of appearance vary with dif- 

 ferent sorts of Ephemera, which are not therefore strictly May- 

 flies. That figured in our plate is a large common species,t 

 which we have noticed late in May, and early in June, sporting 

 in groups of few or many, near the banks of the New River at 

 Hornsey. Its most usual hours of appearance have been from 

 seven till eleven in the morning, and from about sunset until 

 dusk. We may here observe, that confinement, instead of 

 abridging, would seem sometimes to prolong the existence of 

 this short-lived creature ; for of some of the above species put 

 into a box, at night, several were found living in the morning. 



Some of these insects appear in England even as late as 

 August : and Rennie speaks of having noticed them on the 

 Rhine in the same month of 1829, when appearing in the 

 evening all were dead before sunrise. He describes them as 

 <( so thickly strewn in the great square at Wiesbaden, that it 



* Baetes. f Ephemera 



VOL. II. E 



