186 



INSECT ARCPIITECTURE. 



whole by adding a broad piece longer than the rest 

 lo shade his door-way over-head, so that he may not 

 be seen from above. A more laborious structure is 

 reared by the grub of a beautiful caddis-fly (Phry- 

 ganea)^ which weaves together a group of the leaves 

 of aquatic plants into a roundish ball, and in the in- 

 terior of this forms a cell for its abode. The fol- 

 lowing figure from Roesel will give a more precise 

 notion of this structure than a lengthened description. 



Another of these aquatic arcliitects make choice 

 of the tiny shells of young fresh-water mussels and 

 snails [Planoi^bis), to form a moveable grotto, and 

 as these little shells are for the most part inhabited, 

 he keeps the poor animals close prisoners, and drags 



Shell Nests ef Caddis-Worm.% 



