260 A nual s Eutonwlogiail Society of America [Vol. X, 



The fifth tribe, the Allotriini, lacks the frontal carina; the 

 front more or less concave; and tarsal joints three and four 

 lamellate at least on anterior tarsi. This tribe is closely allied 

 to the next. 



The sixth tribe, the Dimitini, also lacks frontal carina; front 

 slightly declivious and fiat; posterior coxae incomplete exteriorly, 

 that is to say, obliterated at the point nearest the metathoracic 

 epimera. This is a very small tribe in which is placed the 

 anomalous genus Anthracopteryx of Horn. 



The seventh tribe, Hypodesini, is erected for the single 

 genus Ilypodcsis of Central America and Mexico and dis- 

 tinguished by the convex front; large antennal fossae; frontal 

 carina obliterated above the point of insertion of labrum; 

 super-antennal ridges oblique and short; mouth inferior; 

 tarsal joints two, three and four lamellate; and tarsal claws 

 simple. Intermediate between the Dimitini and the Cardiorhini. 



The eighth, the Cardiorhini, is a very natural tribe and 

 easily defined by the large bilobed labrum, which character 

 alone suffices to distinguish these insects which are inhabitants 

 of Tropical America. All the species belong to the genus 

 Cardiorhiiius. This tribe, with the three preceding, cannot 

 even be placed hypothetically until the larvae have been 

 discovered. 



The ninth, the Physodactylini, is a tribe erected by O. 

 Schwarz in Genera Insectorum (1906) to receive five small 

 genera from Africa and South America, all of which, with the 

 exception of the type genus PhysodactyJus formerly referred to 

 the Cebrionidae, are quite recent. 



That many discrepancies will be found in this arrangement of 

 the Elateridas is inevitable, for though I have examined larvae 

 of most of the holarctic genera, only a sparse representation of 

 the world's Elateridce are known. The holarctic fauna is 

 extremely weak in Elaterid representatives as compared with 

 the more tropical regions. The great centers of Elateridae at 

 the present time seem to be the Indo Malayan region and 

 Tropical America. Larvae of but one or two genera from these 

 regions are known. About six thousand species of Elateridae 

 have been described for which five hundred and forty-eight 

 genera have been erected. Therefore, we have seen rep- 

 resentatives of less than one-tenth of the known genera in the 

 fa mil v. 



