2918.] 



F. H. Gravely : Passalidae of the World. 



79 



Ophrygonius, p. 86. 



The dentition complete in unworn specimens on both mandibles ; 



the mandibles in most species symmetrical ; the elytra often 



hairless except at the shoulders 

 The lowest terminal and anterior lower teeth of the ri^ht 



mandible absent, or represented only by very minute 



denticles ; the anterior lower tooth of the left mandible very 



large ; the elytra more or less extensively hairy at the sides Aceraius, p. 89. 

 ( The dentition of the left mandible not more reduced than that 



of the right and the right outer tubercle at least as large as 



the left ; the mentum without primary scars ; the secondarv 



scars very large, more or less completely cutting off the 



median from the lateral pieces, usually more or less linear ; 



the lateral and intermediate areas of the metasternum never 



fused 

 Not as above ; the dentition of the right mandible never more 



reduced than that of the left 



The anterior margin of the labrum with a (frequentl)' indistinct) 

 tooth near the middle ; all the elytral grooves deeply 

 impressed throughoat, at least the lateral ones strongly 

 punctured ; the pronotal scars hairless ; at least one of the 

 outer tubercles more or less complex, or truncate with an 

 additional tubercle between itself and the anterior angle of 

 the same side of the head (Oriental forms) 

 The anterior margin of the labrum not toothed ; some at least 

 of the elytral grooves feebly impressed and more or less 

 obsolete behind, none of them at all strongly punctured ; the 

 pronotal scars more or less hairy ; the outer tubercles acute 

 or truncate, but never complex or associated with secondary 

 tubercles (Celebean forms) 

 The mentum with well developed primary scars ; the lateral 



and intermediate areas of the metasternum distinct 

 The mentum without definite primary scars ; or, the lateral and 



intermediate areas of the metasternum fused 

 The lateral and intermediate areas of the metasternum fused . . 

 The lateral and intermediate areas of the metasternum not 



fused 

 The dentition of both mandibles complete, normal ; mandibles 



more or less symmetrical 

 The dentition of both mandibles reduced — especially that of 

 th left one ; the anterior lower tooth (when present) widely 

 separated from the middle lower tooth, and partially fused 

 with the lowest terminal tooth . . . . . . Protomocodus, p. 107. 



8. 

 9, 



Pelopides, p. 93. 



Plesthenus, p. 96. 

 Mastochilus, p. 97. 



10. 

 11. 



12. 



Labienns, p. 103. 



1 The fusion is less obvious than in the American forms where it occurs, as the greater part at least of the posterior 

 -intermediate areas are hairless and either smooth or coarsely punctured, while the areas on the outer side and in front of 

 -them are very hairy and densely but somewhat finely punctured. 



