78 ON ARTIFICIAL FLIES. 



and thus the reproduction of the species pro- 

 ceeds. 



The Phryganidae, to which large family the 

 majority of the flat-winged flies, bred in the water, 

 belong, present very marked characteristics ; the 

 wings, four in number, are much longer than the 

 body and lie flat along the back. The body, when 

 compared to that of an Ephemera, is thick, short, 

 and tapered very slightly ; there is no tail, but 

 two long feelers project from the head. Soon 

 after the eggs are hatched, the grub, commonly 

 known as a " caddis," commences collecting a most 

 extraordinary conglomeration of all sorts and de- 

 scriptions of pieces of stone, gravel, stick, sedge, 

 &c., out of which it proceeds to construct a case of 

 such dimensions and proportions, that it is just able 

 to house itself comfortably in it. The tiny atoms 

 of which this case is built are cemented together 

 by a glutinous compound which exudes from the 

 grub itself; the thin end of the case, corresponding 

 to the tail-end of the grub, is closed, and from 

 the other end the head and a considerable portion 

 of the body of the grub may be seen protruding as 

 he is crawling along on the gravel of a shallow, 

 dragging his little house after him. The selection 

 and distribution of the materials of which the case 

 is constructed are so carefully selected that the 

 presence of a single bubble of air will cause the 

 entire structure, with its inmate, to rise and float, 

 tail upwards, on the surface of the water, while at 



