STUDIES OF VARIATION IN INSECTS 



251 



Fig. 42. Frequency polygon of the variation in measurement C (see fig. 34) 

 in right fore wings of 189 male black ants, collected at one time'in one place ; 

 mean 13.53 micrometer units; index of variability 1.144; coefficient of varia- 

 tion 8.5. 



Fig. 43. Frequency polygon of the variation in measurement D (see fig. 34) 

 of the left fore wings of 196 male black ants, collected at one time in one place ; 

 mean 20.3 micrometer units; index of variability 1.396; coefficient of variation 

 6.S7. 



