224 



KELLOGG AND BELL 



The mean breadth is 67.9 (units of the micrometer), the mode 

 (most frequent breadth) is 68, the standard deviation 1.8 (units 

 or the micrometer) and the coefficient of variation 2.65. The 

 frequency curve is a nearly symmetrical unimodal curve, i. e. 

 variation in size of the wing follows the law of error. 



The frequency polygon showing the variations in length of 

 the vein part, b-d (see fig. n) and the frequency of the various 

 classes in a series of 300 individuals is as follows : 







........ HSaieSiH 



FIG. 13. Frequency polygon of the variation in measurement b-d (see Fig. 

 II ) in the right fore wings of 300 drone honey bees taken from laboratory hive 

 at one time; mean length of this vein part 27.5 micrometer units; index of 

 variability 1.422; coefficient of variation 5.24. 



The mean length of this definitely subtended bit of vein is 

 27.5 (units of micrometer scale) the mode (most frequent length) 

 27 (units of the micrometer), the standard deviation 1.42 -f (units 

 of micrometer) and the coefficient of variation 5.24. There is 

 thus a relatively much larger variation in this measurement than 

 in the breadth of the same wings. 



