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tion in costal hooks of the left hind wings in these lots is as 

 follows : 



Workers: Range 20 to 25, mean 22.1, mode 22, standard 

 deviation 1.36, coefficient of variation 6.15 (see fig. 26). 



Drones: Range 17 to 26, mean 21.1, mode 22, standard 

 deviation 2, coefficient of variation 9.53 (see fig. 27). 



Five lots of ten workers each, taken from five different hives 

 and put together to form one mixed lot of 50 show the follow- 

 ing variation in the hooks of the left hind wings ; range 16 to 

 24, mean 20.6, mode 20, 21 and 22, standard deviation 1.85, 

 coefficient of variation 9 (see fig. 28). It is interesting to note 





FIG. 28. Frequency polygon of the variation in number of costal hooks of 

 the left hind wings of 50 worker honey bees taken in lots of 10 from five different 

 hives; mean 20.6; index of variability 1.85 ; coefficient of variation 9. 



how much larger the coefficient of variation is for this lot of in- 

 dividuals of miscellaneous heredity, five times as much heredity, 

 if it may be so expressed, being represented in this lot of 

 50 workers as in the one of 50 workers taken from a single 

 hive (mentioned in the paragraphs above) ; the coefficient of 

 variation for the 50 workers representing five different mothers 

 being 9, while for the 50 workers of one mother it is but 6.15. 

 This illustrates well the need for homogeneous material whose 

 history is known in the comparative study of any variation 

 within the limits of a species, as the relative variability in the 

 sexes, of one character as compared with another and the like. 

 In our comparative study of the variation in workers and drones, 

 the two largest lots, of 300 individuals each, were taken from 

 the same hive at approximately the same time (about Novem- 

 ber i) and all are offspring of one mother. 



