STUDIES OF VARIATION IN INSECTS 



239 



Fig. 32. Frequency polygon of the variation in number of costal hooks of 

 right hind wings of 52 worker honey bees taken from cells in laboratory hive ; 

 mean 19.6; index of variability 1.24; coefficient of variation 6.33. 



In another lot of 74 workers taken from cells in another hive 

 the variation in hooks is as follows : 



Fig. 33- Frequency polygon of the variation in number of costal hooks of 

 the left hind wings of 74 worker honey bees taken from cells and among young 

 in hive No. 8 at onetime; mean 21.48; index of variability 1.637; coefficient 

 of variation 7.62. 



The range in left wings is from 18 to 25, the mean 21.48, the 

 mode 21, the standard deviation 1.637, and the coeihcient of 

 variation 7.62. 



Comparing now the variation in the number of costal hooks 

 (whose importance in relation to the successful life of the bee is 

 indicated on p. 231) on the hind wings of individuals which have 

 been exposed to the struggle for existence, /. c, have tested in 



