LA.MELLICORNIA. 17 



Differences of coloux' or of the sculpturing of the upper surface 

 distinguish the sexes in various groups, and these probably result 

 in most cases in making the females less conspicuous than the 

 males, by a closer assimilation to their usual environment, or 

 perhaps afford them special protection at the time of egg-laying, 

 when they and their progeny are exposed to the greatest danger. 

 The colour of the male is frequently brighter, as in many species 

 of Macronota and Anoniala, and in the large Chalcosoma atlas already 

 mentioned, the male of which is metallic green and very smooth 

 and brilliant, while the female is dull and slightly hairy. In 

 many of the Valgini and Hopliini the males are decorated with 

 bright-coloured scales, which do not appear or are much reduced 

 in the other sex. 



There are many other differences which have, or may be assumed 

 to have, a more direct relation to the functions of the respective 

 sexes than those which have been mentioned. The caudal style 

 of the female Charitovalgus is evidently of use in oviposition, 

 although the difference of habit which must exist between it and 

 other closely allied genera has not yet been ascertained. The 

 frequent difference between the sexes in the antennae has already 

 been referred to. In Melolonthinj^ and Rutelin.e a larger club 

 is almost universal in the male, the component joints being longer 

 and in some of the former more numerous, the footstalk in the 

 latter case being of course proportionately reduced. Similar 

 differences are found in other groups, but less frequently. 



I have already mentioned the enlargement of the claws of many 

 male Rutelinve and others. This usually occurs only in the inner 

 claw of the fore-foot, the claw-joint being generally correspond- 

 ingly enlarged and the whole tarsus thickened and shortened. In 

 certain Dtnastin^ the enlarged claw is cleft or toothed, but in 

 the RuTELiN.E the reverse condition is not uncommon, this claw 

 being cleft in the female but entire in the male. Occasionally, as 

 in some species of Parastasia, the disparity occurs in the claws of 

 the middle foot. In some Melolonthin^ and EuxELiNiE the 

 front tarsal joints of the male bear broad hairy pads beneath. 



The abdomen of the male is often arched or hollowed beneath 

 or otherwise different from that of the female, and in certain 

 instances where a stridulating apparatus is borne upon the dorsal 

 part it is found to present differences in the two sexes, perhaps as 

 a consequence of the different form of the abdomen or its greater 

 muscularity in the male. 



A multitude of other differences, affecting almost every part of 

 the body, might be enumerated, but enough have been mentioned 

 to show that in the Lamellicornia these sexual disparities are of 

 more than usual importance and interest. 



Food and Hahits. 



Most Lamellicorn beetles feed during the larval stage upon 

 dead vegetable or animal matter, and in the adult period upon the 

 same substances or the juices of plants. The eggs, so far as they 

 have been observed, are spherical or shortly elliptical in shape, 



c 



