STUDIES OF VARIATION IN INSECTS 



237 



To compare the variation in hooks among individuals not yet 

 issued from the hive, i. ., not yet having made any use of the 

 hooks in their life, but nevertheless with the definite comple- 

 ment of hooks fully developed for each individual, we examined 

 a lot of 200 drones taken from cells in our laboratory hives 

 (Italians) the same lot previously studied for variation in venation 

 (see p. 218). 



The frequency polygon graphically showing the variation in 

 the hooks of the left hind wing in these individuals is as follows : 



FIG. 29. Frequency polygon of the variation in number of costal hooks of 

 the left'^hind wings of 200 drone honey bees taken from cells in laboratory hive 

 at one time; mean, 23.36; index of variability 1.6; coefficient of variation 6.8. 



The range in number of hooks is from 20 to 28, the mean 

 23.36, the mode 24, the standard deviation 1.6, and the coeffic- 

 ient of variation 6.8. 



The variation in the right hind wings is graphically shown in 

 the frequency polygon on p. 238 (fig. 30). The range is from 

 19 to 28, the mean 23.15, the mode 23 (with 24 practically 

 equally frequent), the standard deviation 1.71, and the coeffi- 

 cient of variation 7.38. 



The variation in a lot of 50 (approx.) workers taken from 

 cells in our laboratory hive was determined. In the left hind 

 wings it is as shown graphically in the frequency polygon on 

 p. 238 (fig. 31). 



Proc. Wash. Acad. Sci., Dec., 1904. 



