VIII MAY-FLIES 291 



" The full-fed larvae pass from their burrows into 

 the water, and thence into the air, but as no animal is 

 without its enemies, so these larvae, as soon as they 

 enter the water are pursued by Fishes, and when 

 they leave the water for the air, they are immediately 

 liable to be devoured by Birds. All anglers know 

 that the larvae make excellent bait for Fishes. When 

 they emerge from the water, they are often thick as 

 falling flakes of snow. Hence the Dutch proverb, Het 

 isser soo digt, als Haft (as thick as May-flies). At all 

 times of the year when the weather is favourable for 

 fishing, these larvae form an excellent bait. When the 

 waters are high, it is not easy to fetch them out of 

 the mud, and it becomes necessary for some one to 

 strip himself naked and go down after them. I have 

 sometimes sent a man into the water to procure a 

 supply of larvai for dissection. The larvae are tena- 

 cious of life, and live long on the hook, but when 

 taken out of their tubes and placed in water mixed 

 with earth, they do not live more than two days. 

 To keep them alive, they should be placed in wet 

 sand or mud. In this way I have seen the older 

 larvae live four^days, the younger ones eight days ; 

 but when completely submerged, they cannot long 

 be kept alive.^ If it is desired to send live larvae to 



the larvcB of different species varies considerably. Some feed 

 upon living Crustacea, and have a " weel " in their throat to 

 prevent the escape of the victims. I have seen such a structure, 

 not unlike that of Corethra, very plainly in a cast skin of an 

 Ephemera larva, which I was unfortunately unable to deter- 

 mine. 



^ It seems strange that a larva which is habitually submerged 

 should perish when submerged in captivity. The explanation 



U 2 



