10 PLAS £E “CCKX, 
rally form a fort of covering, or tube, for their defencelefs bodies. 
It is open only at one end, at which its head and fore legs are pro- 
truded, to take its prey. Some fpecies form thefe coverings of 
weeds and fmall fhells, gravel, fand, &c. That of our prefent 
fpecies, is compofed of little pieces of the flalks of grafs, cut into 
an even form, and laid tranfverfely on each other. It attaches this 
tube to the roots of fome aquatic plants, and undergoes its transfor. 
mations init. In the annexed plate, we have reprefented the larva 
taken from the tube, and the pupa tae the tube opened to exhibit 
its fituation therein. 
The Fly is very common about ponds, rivers, and marfhy places. 
PLATE 
