120 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[514 



PLATE XXV 



Explanation of Plate 



Figure^ 471. Showing the range of variation in the group of races falling 

 under C. purpurea Oliv. General plan of arrangement as in the preceding charts 

 on other species (Pis. XXI and XXIII). In the case of this species the immacu- 

 lated elytroned types which are very rare in occurrence are taken as a central 

 type. Those to left are level ground inhabitants in which the reduction of pat- 

 terns is characterized by a withdrawal of the middle band from the elytral mar- 

 gin. Those to the right are the steep clay bank inhabitants, except possibly class 

 "t" (C. decemnotata Say); classes a, b, c. C. ciinarrona Lee; d-h, C. purpurea 

 Oliv., graminea Schpp., audobonii Lee, spreia Lee. Those to the right are splen- 

 dida, Hentz, transversa Leng, denvcrensis Cas., limbalis Klg. The graphs are for 

 the following localities with approximate altitudes, vegetation, etc. 



Climate 



