252 A NATURALIST IN THE GREAT LAKES REGION 



prairie, if its subsoil is clay, is 

 the abundance of chimneys of 

 the burrowing crayfish, Cam- 

 barus gracilis (green) (Fig. 379) 

 and C. diogenes (red). These 

 animals dig wells to insure 

 moist retreats in the dry sum- 

 mertime and safe ones at all 

 times. The excavated mate- 

 rial is often piled as a chim- 

 ney about the hole. The 

 crayfish lives near the top of 

 the burrow but drops back 

 when frightened. He wanders 

 out from his castle turret to 

 seek food, hunting largely at 

 dusk. Earthworms are com- 

 mon in the rich prairie soils, 

 particularly the big night 



crawler. Larvae of the Tune 

 FIG. 373- Rosinweed, Silphium . j x j.i. 



terebinthinaceum. beetle ar abundant in the 



subterranean layer of the 

 upland prairie. The ant, 

 Formosa subpolitavar neo- 

 gagates, builds large hills, 

 burrowing into the ground 

 beneath them. The star- 

 nosed mole, similar to the 

 common mole, but easily 

 recognized by its large 

 front feet with heavy claws 

 and the fringed disk on its 

 nose, burrows beneath the FIG. 3 ?4 FIG. 37 s 



sod for worms and larvae. c ^5.374,375: Fig. 374 .-Dn>pseed [grass, 



Sporobolus cryptandrus; Fig. 375. Prairie 



The familiar striped gopher phlox, Phlox pttosa. 



