334 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



$ FIG. 326. Fl - 327 ' 



A COMPARATIVE VIEW OF THE NESTING ARMOR OF RHIZOPODS, CADDIS FLIES, AND BAG WORMS. 

 FIG. 320. Case of Caddis (Limnophilus flavicornis), made of minute shells. FIG. 321. Case of gravel, 

 made by the larva (Fio. 322) of a Caddis fly. FIG. 323. Case of Caddis worm (Limnophilus rhom- 

 bicus), made of moss. FIG. 324. Case of Caddis (Limnophilus pellucidus), made of pieces of 

 leaves. FIG. 325. The basket or thatched bag of the Bag worm (Theridopterix). FIG. 326. Shell 

 of a Rhizopod, Difflugia urceolata (variety amphora), built up of quartz sand. X 100 diameters. 

 (After Leidy.) FIG. 327. Shell of Rhizopod, Difflugia acuminata, composed of quartz sand and 

 diatoms. X 200 diameters. (After Leidy.) 



