ADEPHAGA. 21 



reticulation of the elytra being generally rather broader and shorter than 

 in the ordinary temperate European form. This form has been found 

 by Kiesenwetter in the Alps of Carniola ; and has also occurred at 

 Lago Pinter, and in the Hautes Pyrenees ; it may be called the 

 monomorphic Alpine form. 



" We have thus the peculiar anomaly that in some Alpine districts the 

 sexual divergence in sculpture of the female from the male is much 

 increased, while in other Alpine districts there is on the contrary con- 

 vergence of the sculpture of the female to the male, or in fact absolute 

 similarity. I have no evidence that these two Alpine forms of the 

 female are ever found together, indeed all the evidence I have indicates 

 the contrary ; thus though I have found great numbers of the dimorphic 

 Alpine form in the mountains about Braemar, I have never found a 

 single female with sculpture at all like that of the male, while the 

 females before me from Lago Pinter, seven in number, are all similar 

 to the males. There thus appear to be two Alpine races, the males 

 of the two being similar while the females are very diflerent. The 

 species, however, not only varies in sculpture both absolutely (that is in 

 both sexes considered together) and sexually, but it shows quite as 

 great and even more interesting modifications, in what may be called 

 quite structural characters ; thus the shape becomes in the Alpine 

 forms quite different from that obtained in the plains, and in corre- 

 spondence with this modification of shape is a change in the legs, which 

 are very much more elongate and slender (that is less highly developed 

 for swimming) than they are in the individuals of the plain ; this 

 diminution in the power of the legs reaches its extreme in the most 

 divergent females of both the Alpine forms. 



" The male tarsi also are subject to much variation, the amount of 

 their incrassation and the sexual structure of the front claws being each 

 inconstant ; the greatest development of the male feet and claws is 

 found in the large individuals of the plains, the smallest in the Alpine 

 forms ; in these latter the amount of dilatation of the tarsus is greatly 

 diminished, and the posterior of the claws on the front feet becomes 

 more slender, the dilatation of its hinder edge being in extreme cases 

 very greatly diminished ; the fi-ont claws moreover are variable 

 independently of Alpine or boreal localisation, for I have a male (from 

 Corsica ?) in which the anterior claw retains pretty nearly the normal 

 shape, but is not longer than the front one. 



" It seems very difficult to comprehend these variations. Especially 

 peculiar seems the fact that the males of Alpine and boreal districts 

 depart from the dwellers of the plains in one direction only, and yet 

 their females depart in two opposite directions ; equally difiicult of 

 explanation is the fact that though disparity in sculpture of the sexes 

 is the rule, yet this disparity disappears in the two forms which in 

 other respects are most widely different from one another, viz., the 

 large and powerful South European variety, and the feeble, mono- 

 morphic Alpine variety ; we seem, however, at any rate, jvistified in 



