238 



KELLOGG AND BELL 



Fig. 30. Frequency polygon of the variation in number of costal hooks of 

 the right hind wings of 200 drone honey bees taken from cells in laboratory 

 hive at one time; mean 23.15; index of variability 1.71; coefficient of varia- 

 tion, 7.38. 



The range is from 18 to 23, the mean 20, the mode 20, the 

 standard deviation 1.19, and the coefficient of variation 6. 



Classes /g 



Fig. 31. Frequency polygon of the variation in number of costal hooks of 

 the left hindjwings of 54 worker honey bees taken from cells in laboratory hive ; 

 mean 20; index'of variability 1.19; coefficient of variation 6. 



In the right hind wings it is as shown b}' the frequency poly- 

 gon on p. 239 (fig. 32). The range is from 16 to 22, the mean 

 19.6, the mode 20, the standard deviation 1.24, and the coeffi- 

 cient of variation 6.33. 



