26 



D. B. CASTEEL AND E. F. PHILLIPS. 



they are not therefore good tests of the comparative variability, 

 then, since vein m is entirely outside this area, this measurement 

 would serve as an answer to that argument and is in itself a 

 sufficient test. As in the case of vein M 2 , the measurements of 

 this vein were made principally for the sake of getting a ratio of 

 variation between two veins which meet at nearly a right angle, 

 but as the drones show greater variation than the workers, al- 

 though not to so great a degree as in some other cases, and as 

 this is a constant vein, we add the table. The greatest range in 

 workers is 16 mm., the least in drones 15 mm.; the average for 

 workers almost 13 mm., the average for drones 20 mm.; the 

 greatest for drones 23 mm. The average lengths in the two cases 

 (72 mm. and 97 mm.) reduces this difference about one third, so 

 that the least variable drones are about as constant as the least 

 variable workers, but the average range for drones still remains 

 considerably greater than for workers. 



TABLE IV. 



VEIN m. 



Drones. 



Workers. 



