4 o 



I will now state my reasons for what I believe to be 

 the cause of the decrease of the May fly, or natural 

 drake. The first and most important is the sewage from 

 large towns being allowed to drain into the rivers, and 

 mixing with the gravel in the river beds where the drake 

 breeds, to a certain extent poisons it. To prove this, I 

 have often, when a lad, waded into a stream during the 

 month of May, for a spadeful of gravel, to examine the 

 chrysalis ; semetimes it was a moving mass. I have 

 proved they were the natural May fly, by putting the 

 gravel containing the chrysalis into a perforated box, 

 sinking it into the bed of the river and allowing it to 

 remain until they were hatched. On opening it I have 

 found several drakes perfectly hatched, but drowned. I 

 have tried the same plan recently, and in a spadeful of 

 gravel have only found two or three chrysalis, where 

 formerly there were hundreds. This fact is much to be 

 regretted, and my opinion is that, unless the sewage be 

 kept from the rivers, in a few years the May fly will 

 become almost extinct. 



Secondly, a great cause of its decrease is owing to the 

 number of enemies waiting to devour it the moment 

 it is hatched. The swallows take them by thousands; 

 the water wagtail, the reed sparrow, and, in fact, all the 

 small birds feed freely upon them ; and I have often been 

 much amused to see how cleverly the birds will pick them 

 off the water. The ducks, too, will soon clear them off a 

 stream. 



Lastly, the voracious trout, when they commence 

 feeding, take every drake that comes in their way, and 



