20 RUTELINjE. 



A surprising distinction is the occurrence of a longer mesosternal 

 process in the female than in the male. I first called attention to 

 this in the Malayan Parastasia mirabilis (an announcement which 

 was received with some scepticism), but a second instance is 

 pointed out here in P. sulcipennis. Whether these curious and 

 varied differences have any functional significance or nor, observa- 

 tion may perhaps eventually determine. None can be suggested 

 in the present state ot our knowledge, either for those just 

 mentioned, or for the modifications of the male anatomy which 

 follow. 



In several genera a slight dilatation of the clypeus is found in 

 that sex, the front margin being straighter, more strongly reflexed, 

 and more angular at the sides than in the female, which has it 

 simply rounded. This is found in the Australian genus Anoplo- 

 gna+hus, the American Phalangoyonia, and in several unconnected 

 groups of Anomala (e. g., A. dorsalis, A. teneHa, A. lateralis, etc.). 

 Aiiomala armata, although one of a group of exceedingly 

 similar species, and whose female can only with difficulty be dis- 

 tinguished from that of A. strigata, is unique in having in the 

 male a strong backward-pointing process to the hind femur, but 

 a similar effect is produced in the same sex of A. trocltanterica and 

 Tropiorrhytichus podayricus by the sharp projecting trochanters. 



A much more striking disparity than any of these characterises 

 the very remarkable Peperonota harringtoni (figs. 8 & 9), the male 

 of which has the pronotum prolonged backwards into a strange 

 tail-like appendage. To accommodate this the scutellum and the 

 adjoining part of the elytra are considerably depressed. Closely 

 allied to this is Dicaulocephalus feat (Plate I, fig. 1), in which the 

 mandibles of the male (the female is still unknown) have enor- 

 mous outwardly-turned prolongations. Didrepanepliorus bifalcifer 

 (Plate 1, fig. 5 & 6) is still more extraordinary, its mandibles being 

 produced forwards and curved upwards like a pair of elephant's 

 tusks. In the males of Fruhstorferia (text-figs. 14 & 15) the 

 mandibles are calliper-shaped. In none of these armatures, how- 

 ever, does any offensive or defensive purpose seem really probable, 

 for the actual gripping-power is in inverse ratio to the degree of 

 elongation of the mandibles, which become exceedingly delicate 

 and brittle, while there appears to be no increase of musculature. 

 Tet another male feature, to which I know of no parallel in 

 Lamellicorn beetles, is worthy of mention. It is found in 

 Adoretus celogaster, in which that sex exhibits a rounded boss or 

 tubercle at the middle of each ventral segment. 



Differences of coloration between the two sexes are not very 

 numerous, but there are sufficient to provide a pitfall for in- 

 cautious systematists who may be content to rely only upon a 

 feature so superficial as pattern in the determination of species. 

 Amongst those not very numerous species that have a definite 

 pattern, I have found several cases in which the patterns of the 

 male and female are strikingly different. This becomes more 

 perplexing from the fact that, with the exception of a very few 



