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KELLOGG AND BELL 



the variation in number of the tibial spines on the hind legs. 

 The range and frequency of this variation is shown in the fol- 

 lowing frequency' polygons : 



Fig. 62. Frequencj' polygon of the variation in number of spines in the 

 outer row of the right],tibije in 39 male red-legged locusts, AIela7ioplus fetnur- 

 rubriim. 



From these polygons it will be noted that the range is, in 

 outer row, right tibia, males, 9 to 15, females 11 to 15; left 



Fig. 63. Frequency polygon of the variation in number of spines of the 

 outer row on left tibia; of 39 male red-legged locusts, Melanopiiis fcmiir-ruhntm. 



tibia, males, 9 to 13, females 10 to 14 ; in inner row, right tibia, 

 males, 11 to 14, females 10 to 14, left tibia, males, 11 to 14, 



