INTRODUCTION. 1 9 



which are always simple iu the AXOMALINI and ADOBETIM, are 

 here usually cleft in the male or in Doth sexes. In a curious ne\v 

 genus of ADOKETINI described later (Lissadoretus) the rule is also 

 reversed, and the female has all the claws simple, while the male 

 has the longer front and middle ones divided. The peculiar 

 build of the female in this case seems to suggest an adaptation to 

 some special and non-arboreal mode of life. 



Iu one small group of Malayan species of Parastasia the middle 

 feet of the male are specially modified, instead of the front ones, 

 the outer claw of each bearing a broad flat. lobe. 



I have mentioned that a sexual difference in the form of the 

 front, tibia is common, but the hind tibia is almost equally liable 

 to differ. That of the female is commonly shorter and broader 

 than that of the male and dilated at the end. Probablv this 

 modification, of shape enables the female better to perform the 

 digging operations involved in the deposition of her eggs. 



In a few species of Anomala, a curious difference in the spurs 

 at the end of the hind tibiae manifests itself. The longer one 

 of the two spurs, in the males of A. pterygopliorus, A. stoliczkce. 

 A. antliracina and A. propinqua, is lengthened, strongly curved, 

 and blunt or knobbed at the end, while in the females both spurs 

 are straight and acute. A. propinqua and A. antliracina are onlv 

 remotely related to the other two species mentioned, so that this 

 appears to be an instance of an almost identical modification 

 arising independently. 



Of similar significance to the modified feet of the males are 

 certain features characterising the females of manv species. For 

 instance, a structure found in the females of many DYNASTIN^; 

 (Cyclocephala, etc.) recurs in various genera of KUTELIX.E (Pelto- 

 notus, Frulistorferia, certain species of Anomala, etc.). This is an 

 abrupt thickening or expansion of the outer margins of the elytra 

 at a point usually just behind the middle. In Parastasia sulci- 

 jiennis (figs. 11 & 12) and various allied species, the elytra, which 

 in the male are peculiarly smooth and glossy, bear in the other 

 sex very deep furrows, which, combined with other differences 

 of colour and shape, give the two sexes a totally different aspect 

 In Anomala rugosa (tigs. 39 & 40) the elytra of the female are 

 very finely sculptured in such a way as to be quite dull in 

 appearance, while in the male they are shining, and in A.flavo- 

 notata there is a similar, although smaller, difference. Dis- 

 parities of a rather similar kind are not uncommonly found 

 in the pygidium and propygidium. Thus in Parastasia rufo- 

 picta (Plate I, fig. 4) the propygidium of the male has a silky 

 lustre, but in the female it has a highly peculiar dense granu- 

 lation which produces a kind of sooty surface. In an allied species, 

 P. basalis, the propygidium is the same in both, but the pygidium 

 is covered with hair in the female and bare in the male. An 

 exactly similar difference is found in Anomala dimidiala and other 

 species of Anomala, although the relationship between the genera 

 Parastasia and Anomala is remote. In other cases a slight dif- 

 ference in the sculpturing of the pygidium distinguishes the sexes. 



c2 



