36 FOOD OF FISHES. 



when taken from their cases, make excellent baits for 

 almost every sort .of fish ! . 



Grubs of Day Flies, and other Insects. 



The grubs or young of the various species of day 

 flies known to naturalists by the term Ephemeridas, and 

 to anglers by the various names of duns, drakes, and 

 may flies, such as the dun drake or march brown, the 

 blue dun, the green drake or green may fly, are often 

 found in considerable abundance about the roots of 

 water plants, and in the clay forming the banks of 

 ponds and canals, in which they excavate burrows for 

 themselves under the level of the water, an operation 

 well described by Scopoli, Swammerdam, and Reau- 

 mur. The excavations are always proportioned to the 

 size of the inhabitant ; and consequently, when it is 

 young and small, the hole is proportionably small, 

 though, with respect to extent, it is always at least 

 double the length of its body. The hole, being under 

 the level of the river, is always filled with water, so 

 that the grub swims in its native element, and while 

 it is secured from being preyed upon by fishes, it has 

 its own food within easy reach. It feeds, in fact, if 

 we may judge from its egesta, upon the slime or 

 moistened clay with which its hole is lined. In the 

 bank of the stream at Lee, in Kent, I found an old 

 willow stump full of holes stuffed with clay, in which 

 the grubs in question nestled securely. 



(l) For other details respecting these, see my Insect Architecture, 

 chap. x. 



