214 SALMONIA. 



me to be the cast-off skins of the small spe- 

 cies of ephemerae on the banks of rivers and 

 floating in the water. The green ephemera, 

 or May fly, lays her eggs sitting on the 

 water, which instantly sink to the bottom: 

 and most of the duns, or small slender- 

 winged flies, do the same. The grey or 

 glossy-winged May fly, commonly called the 

 grey drake, performs regular motions in the 

 air above the water, rising and falling, and 

 sitting, as it were, for a moment on the sur- 

 face, and rising again, at which time she is 

 said to deposit her eggs. To attempt to 

 describe all the variety of ephemerae, which 

 sport on the surface of the water at different 

 times of the day, throughout the year, would 

 be quite an endless labour. Some of them 

 appear to live only a few hours, and none of 

 them, I believe, more than a few days. In 

 spring and autumn a new variety of these 

 flies sometimes appears every day, or even 

 in different parts of the same day. Of the 

 beetle, or colyoptera genus, there are many 

 varieties fed on by fishes. These insects, 

 which are distinguished, as you know, by 



