The Ephemerae are the true May-flies of anglers, no less 

 celebrated as a bait for trout, than they are for the shortness 

 of their lives; yet short as the natural term of their existence 

 is, myriads are swept away and devoured by the rising fish 

 before they have escaped from the water which gave them 

 birth. The importance of these insects in the oeconomy of 

 nature is manifest by the immense quantities that are pro- 

 duced, and without them many species of fishes would become 

 extinct. The multitudes of eggs that are deposited by the E. 

 vulgata must be incalculable, for a very small proportion only 

 of the whole can be hatched ; then the larvae living at the bot- 

 tom of the water become a ground bait for fishes, and the prey 

 of predaceous insects in all their stages. The pupa, if it be per- 

 mitted to rise to the surface, must there remain until the fly 

 in its first winged state or Pseud-imago, has time to burst from 

 its shroud, when its soft and heavy wings render its progress 

 to the shore slow and uncertain ; there it alights on a blade of 

 grass or some plant, and casts off its skin again, as related in 

 folio 484, and then it becomes the beautiful fly, which notwith^ 

 standing the myriads that have been destroyed, we still see in 

 myriads undulating over rivers and their banks, in the morn- 

 ings and evenings of calm and fine days in the months of May 

 and June, again to contribute to the support of the finny 

 tribes. 



I am convinced it would well reward any one living in the 

 Lake districts to study this family and the Phryganidae, for I 

 have never visited either Scotland or Ireland without finding 

 new and interesting species, especially of the latter order, 

 which swarms even on the steam-boats ; and the valuable and 

 talented memoir of Mons. Pictet proves what may be done 

 by steady attention to a subject in a favourable locality. In 

 North America, again, a vast and magnificent field must re- 

 main to be explored by some zealous and fortunate lover of 

 these tribes, it is to be hoped at no distant period. 



Having obtained living specimens of the Ephemera, I was 

 able to detect some rudimentary trophi, which seem to com- 

 prise 2 large palpi with 2 lobes below them and a dilated la- 

 bium with 2 divaricating lobes. Imperfect as these oral organs 

 are, I think they are an additional proof of the affinity of the 

 perfect Ephemeridae with the Phryganidae, nearly related as 

 they are in their larva state to the Libellulidse. 



I found both E. vulgata and cognata in the greatest profu- 

 sion on the banks of the river at Oxford the beginning of 

 June, and I am doubtful whether the latter is distinct. Our 

 figure represents the female a little larger than life ; the male 

 is much smaller and darker. 



The plant is Callilriche aquadca, Star-grass. 



