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

 outer row of the right^tibise in 39 male red-legged locusts, Melanoplus femur- 

 rubrum. 



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

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



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

 outer row on left tibiae of 39 male red-legged locusts, Melanoplus femur-rub rum. 



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

 males, n to 14, females 10 to 14, left tibia, males, u to 14, 



