PHENOMENON OF THE " FEED." 93 



only rising at regular intervals for a quarter of an hour 

 at a time, when the whole surface of the water seems 

 alive ; then as suddenly cease for about half an hour, 

 as if to digest their lunch before another onslaught is 

 made. This is most observable on rivers which produce 

 large quantities of the different tribes of ephemerae, be- 

 sides the ordinary aquatic flies, and will only take place 

 at those seasons when they come forth in the winged 

 state ; and as it is the habit of these insects to issue 

 from the larvae state in whole myriads at once, like a 

 swarm of bees, when they take wing, hover over the 

 surface of the water for a few minutes in order to deposit 

 their eggs, then finally disappear. The whole period of 

 their winged existence (given apparently, merely to 

 enable them to perpetuate the species) seldom exceeds 

 a couple of hours, and in certain tribes only a few 

 minutes ; while the utmost limit to which the existence 

 of the longest-lived of the species is prolonged, does 

 not exceed a couple of days. Now the cause of the 

 fish rising only at intervals, is the successive flights of 

 the above coming on the water, tribe after tribe ; when 

 the former gorge themselves as quickly as they can 

 during the time the flight lasts, and immediately retire 

 to wait for another. As the trout are exceedingly 

 partial to these minute insects, which in most cases are 

 little larger than midges, they will seldom look at any 

 other fly the angler can offer. At this time he may 

 make up his mind to bear the tantalizing prospect of 

 fish rising at every part of the water except the parti- 

 cular spot upon which his own flies rest, with as much 



