Mr. H. W. Bates on the Endomychidae of the Amazon Valley. 161 



Dr. Gerstaecker gives statistics to show that the large-sized species 

 of Endornychidae (the EumorpTimi) exist in far greater numbers in 

 the tropics of the Old World than in those of the New. The species 

 of the former are to those of the latter in the numeric proportion of 

 four to one. This shows that they are far more highly developed in 

 one hemisphere than in the other. It is true that the proportion is 

 reversed in the case of the small-sized species (the Dapsini). In this 

 group the Old- World species are to the New, in numbers, as one to four 

 and a half. Notwithstanding this, on looking over a large general 

 collection of the family, the great superiority of the Old- World species 

 in size and variety of forms is very striking. On this account it 

 would be worth while to inquire whether the large Eumorpluni of 

 the East do not occupy there that sphere in the economy of nature, 

 which in America is filled by the large Erotylidae. The latter family 

 in America far surpass in variety and general individual bulk the 

 members of the same group in the Old World. It would be interest- 

 ing, therefore, to know whether the Eumorphini in the East live 

 tipon the same class of large ephemeral fungi in the humid forests, 

 that in America is the peculiar prey of the Erotylidae. When a new 

 sphere of function is opened in nature, it is apparently filled by 

 members of a group whose habits already in some measure fit them 

 for it and who happen to be close at hand for the purpose ; thus it is 

 that similar or the same functions are performed in different parts 

 of the world not always by the same family or group or species, but 

 frequently by an allied group or species. That sphere of action 

 which is filled in one hemisphere by a certain family, in another is 

 filled by an analogous or by an allied family. Instances of this 

 occur in all departments of natural history ; there is a beautiful 

 one in the diurnal Lepidoptera, where the Heliconianae of the New 

 World fill that sphere of action, which in the Old World is filled by 

 the allied groups Acraeanae and Danainae. 



Family Endomychidae. 



Subfamily EraroRrnxN^:. 

 Genus Cortnomalus, (Dejean) Gerstaecker. 



§ A. Elytra gibbous, the convexity towards the middle bulging out so as to 

 conceal part of the lateral margins when viewed from above. 



1. Corynomcdus maximus, n. sp. 



C. subglobosus, piceus, vix nitidus, antennis, articulo basali excepto, 

 tibiisque nigris ; thorace angusto, sublongiore, angidis apicalibus sub- 



