v LAMELLICORNIA DYNASTIDES CETONIIDES I 99 



Insects of brilliant metallic colours amongst them, but very little 

 is known as to their life-histories. The larvae are very much 

 like those of Melolonthides. 



iv. The DYNASTIDES are the smallest division in number of 

 species, there being scarcely 1000 known ; but amongst them 

 we find in the genera Dynastes and Megasoma some of the 

 largest of existing Insects. The horns and projections on the 

 heads and prothoraces of some of the males of these Insects are 

 truly extraordinary, and it does not appear possible to explain 

 their existence by any use they are to their possessors. These 

 structures are but little used for fighting. Baron von Hiigel 

 informs the writer that in Java he has observed large numbers 

 of Xylotrupes gideon; he noticed that the males sometimes carry 

 the females by the aid of their horns ; but this must be an excep- 

 tional case, for the shape of these instruments, in the majority of 

 Dynastides, would not allow of their being put to this use. The 

 development of these horns varies greatly in most of the species, 

 but he did not find that the females exhibited any preference for 

 the highly armed males. The fact that the males are very much 

 larger than the females, and that the armature is usually confined 

 to them, suggests, however, that some sexual reason exists for these 

 remarkable projections. Many Dynastides possess organs of stridu- 

 lation, consisting of lines of sculpture placed so as to form one or 

 two bands on the middle of the propygidium, and brought into 

 play by being rubbed by the extremities of the wing-cases. This 

 apparatus is of a less perfect nature than the structures for the 

 same purpose found in numerous other beetles. We have no 

 member of this sub-family in Britain, and there are scarcely a 

 dozen in all Europe. Decaying vegetable matter is believed to 

 be the nutriment of Dynastides. The European Oryctes nasicornis 

 is sometimes found in numbers in spent tan. The growth and 

 development of the individual is believed to be but slow. 



v. The CETONIIDES are renowned for the beauty of their colours 

 and the elegance of their forms ; hence they are a favourite 

 group, and about 1600 species have been catalogued. They are 

 specially fond of warm regions, but it is a peculiarity of the 

 sub-family that a large majority of the species are found in the 

 Old World ; South America is inexplicably poor in these Insects, 

 notwithstanding its extensive forests. In this sub-family the 

 mode of flight is peculiar ; the elytra do not extend down the 



