93. The pond crayfish, Procain 

 hants hlandinnii acutus, often mi- 

 grates in considerable numbers il 

 night, traveling from one pond 

 to another. (Illinois, [ohn Gerard 

 National .\udiibon) 



94. The burrowing crayfish, Camharus diogencs, digs its home close to a 

 stream, excavating a chamber three or four feet below the soil surface where 

 water will seep into it. A mud chimney several inches high is built around 

 the burrow opening. (Illinois. John Gerard: National Audubon) 



