ENTOMOLOGY. 119 



pair of legs) are, in the larva of the ophimeridaB, 

 flat and fin-like, evidently for the puri)ose of 

 swimming; whilst, in the fore legs, they are 

 round, and, of course, better fitted for pene- 

 trating the bottoms or sides of rivers in search of 

 food. 



Considerable advantage, I am of opinion, 

 would result from laying down certain general 

 rules after the manner of the beautiful, but much 

 overlooked, classification of larvae, by Bergman, 

 which would enable the student, on examining 

 the more important organs of water-bred larvae, 

 to predict the family to which the perfect insect 

 will belong. Thus, whenever we obser\e in the 

 water an insect travelling about, in a larva state, 

 in a pipe or tube of any kind open at the end, 

 we may, I think, safely decide that its wings 

 will be recumbent, in some form or other, when 

 reposing. 



Such a rule, if correct, would long since have 

 settled the point as to that fly, so interesting to 

 anglers, the ephemera vulgata or May -fly, spring- 

 ing from a caddis or straw-worm, as most of 

 our fishing books, from Father AValton down- 

 wards, as well as many distinguished writers on 

 entomology, have erroneously described it ; for it 



