118 ILLIXOIS BIOLOGICAL MONOGRAPHS [512 



PLATE XXIV 



Explanation ok Plate 



Figure 470a. Showing tlie distribution of the group of races included under 

 C. sciitcUaris Say. The legend indicates the color of tlie elytron. The nunibers 

 (italics) refer to the classes of color patterns indicated in figure 470, plate XXIII. 

 The lines and numbers indicate mean annual rainfall in inches. The mean annual 

 rainfall to the left or west of the line designated as 20 is less than 20 inthes, to 

 the right or east more than 20 inches. To the east and south of the line desig- 

 nated as 30 the mean annual rainfall is more than 30 inches. To the east and 

 south of the line designated as 40 it is more than 40 inches. Note that the colors 

 are fairly well correlated with rainfall. 



