STUDIES OF VARIATION IN INSECTS 



233 



The variation in 286 right hind wings (14 individuals had 

 torn wings) is graphically shown in the following frequency 

 polygon : 



FIG. 23. Frequency polygon of the variation in number of costal hooks of 

 the right hind wings of 286 drone honey bees taken from laboratory hive at one 

 time; mean 23.26, index of variability 1.838; coefficient of variation 7.9. 



The range is from 19 to 29, the mean 23.26, the mode 23, 

 the standard deviation 1.838 and the coefficient of variation 7.9. 

 Ninety-eight individuals (34! per cent.) have a smaller number 

 of hooks than the mode (and than the mean) while one hundred 

 and twenty-two (42^ per cent.) have a larger number. The 

 number having the mode is sixty-six (23 per cent.), the same 

 number as in the left wings. 



In 300 workers (Italians) from the same laboratory hive, the 

 lot whose wings have been studied for variation in venation (see 

 pp. 217 and 226), the variation in number of costal hooks in 299 

 left hind wings is graphically shown in the frequency polygon 

 on the following page (fig. 24). 



The range is from 17 to 26, the mean 21.13, the mode 21 

 (with 22 almost as frequent), the standard deviation 1.581, and 

 the coefficient of variation, 7.48. 



The variation in 293 right hind wings (7 individuals of the lot 



