Statistical Stituf.s on tiif, Variation of Staqüeeilfs. 



8i 



In this respect tlic species is provided with two apices around which tlic popula- 

 tion is crowded : the first 

 f»/.- ^ apex corresijontls to the 30 



mm group, while the second 

 falls in tlie 40 mm class. 



From the curve above 



given, it is evident that the 



two apices represent the 



majorit}' of variates: firstly, 



I { I it falls on the 30 mm class 



So SJ -fa 4S 



which exhibits the class of 

 greatest frequency of moder- 

 atcl_\' low individuals, and 

 secondly on the 40 mm class 

 which marks the maximum number of moderatcl}' high types, while all the in- 

 termediate forms (Fig. I. d~f) lie around the sinus, that is 34 mm, which indicates 

 the rarer occurrence ; the 37 mm class marks the higher limit beyond which 

 none of the low types are met with, and the 33mm class the lower limit, 

 which is never crossed bv anv of the high forms. 



Fig. 2. Curve showing frequency of various Iiody 

 lengths of male in Clado<;itathus. Ordinales, iiumder of 

 individuals ; abscissa, body length in mm. 



Female. — In contrast to tiie male which is armed with powerful antlers 

 the female possesses only a pair of inconspicuous mandibles like forceps. 

 The body size of the female is much inferior to that of the male. The 

 largest female attains at most the body length of 34mm, or a point which 

 reaches hardly the height of the male variates of middle length. It their 

 fluctuates and rims straight to the minimum one of 23mm, so that there can 

 not be drawn a distinct line of demarcation, as shown by a comparison of 

 the two individuals (Fig. 3) standing at the extremities of a row in which 

 1333 females are serially arranged according to their body length, i.e. magni- 

 tude. It is evident that the biggest individual {a) is in every respect nothing 

 more than the smallest one {b) magnified. More accurate data can be gath- 

 ered with the same method which consists in the study of the males, in group- 

 ing the total population into certain .^classes according to the body length«- 



