340 ARTICULATA. INSECTA. 



two sickles projecting from the head. When the 

 victim is sucked dry, the body is jerked to a consi- 

 derable distance out of the den. The perfect in- 

 sect has large transparent wings, much resembling 

 those of some Dragon -flies. 



Whoever has for a few moments looked closely 

 into a shallow pool, must have noticed many moving 

 things, like bits of stick, about an inch in length, 

 from one end of which protrude a head and six legs. 

 These are the tubes of the Caddis-worms, the larvae 

 of the genus Phryganea,* well known to anglers. 

 The worm itself constructs the tube for the pro- 

 tection of its soft body, by collecting minute matters, 

 varying in different species, such as bits of twigs, 

 straw, bark, shells, stones, &c., and fastening them 

 each to each around its body with silk spun from 

 its mouth. By carefully depriving one of its case, 

 and placing it in water with a selection of materials, 

 we have witnessed the construction of a new one with 

 great pleasure. The head, thorax, and legs are con- 

 tinually thrust out in search of prey, as the larvce 

 are very voracious. When full-grown, the insect 

 closes the mouth of its tube with a network of silk, 

 and changes to apupa, which at the appointed time 

 craw r ls out of the case and comes upon the land, 

 where it perfects its condition in the manner of the 

 Dragon-fly. The fly resembles a Moth, having 

 brown wings, the upper concealing the lower, and 

 placed, when at rest, like the roof of a house : it 

 flits to and fro over water, chiefly in the evening. 



v 7 phryganon, a dry stick. 



