igi4.] 



F. H. Gravely : An Account of the Oriental Passalidae. 



321 



18. 



14. 



3< 



have seen in each species has been carefuUy noted in the descriptions given in the 

 more extended account of the genus (above pp. 228-240). 



Upper tooth of both mandibles distinct; lowest terminal 

 tooth of right mandible rudimentary or absent; anterior lower 

 tooth of right mandible minute or absent, that of left mandible 



always very large .. .. ■ .-. •■ •• •• 2- 



Upper tooth of both mandibles obsolete ; lowest terminal tooth 

 of both mandibles normal ; anterior lower tooth of right man- 

 dible well developed, that of left si le not always abnormally 



.large 



No convexity of upper margin of left mandible, behind base of 

 hinder margin of simple or bifid upper tooth ; this margin con- 

 cave, straight, or convex the whole way from tip of tooth 

 backwards (see figs. 26a, 271?, 286, 29) 



Upper tooth of left mandible always simple, set in a hollow in 

 front of a convexity of the upper margin from which it is dis- 

 tinctly separated at base (see fig. 25a, pi. xii; & 4C, p. 234) 

 Upper tooth of left mandible very variable ; a small denticle 

 sometimes present below the apex (figs. 28a, 32), but the apex 

 itself not bifid (figs. 26*, 27a, 28, 29, 30, 32, 33) except some- 

 times in species in which the anterior angles of the head are 

 very distinctly prolonged forwards (fig. 286) 

 Anterior angles of the head obtuse, never prolonged forwards ; 

 apex of upper tooth of left mandible always more or less dis- 



.tinctly bifid in unworn specimens (see especially fig. 31) 

 Right outer tubercle simple, elongate, acute (figs. 26, 32, 



\ 33); anterior angles of head truncate or at most moderately 



I prolonged 

 4 ; Anterior angles of head at least moderately prolonged; right 

 outer tubercle usually shorter, truncate or rounded, some- 

 times divided into two separate tubercles of which the outer 



^ one or both may be more or less elongate and acute 



I All six lamellae of antennae very long and slender; inner 

 margin of right outer tubercle parallel to axis of body at base ; 

 5 anterior angles of head not prominent 



(Proximal lamellae of antennae shorter ; inner margin of right 

 outer tubercle oblique throughout 



-• Apex of right outer tubercle truncate or imperfectly bifid in 

 profile, the suture distinctly bent downwards; anterior angles 

 I of head not prominent ; mentum punctured sparsely or not at 

 , ; all in middle (left upper tooth very variable) 



Apex of right outer tubercle simply pointed in profile, suture 

 not bent downwards; anterior angles of head more or less dis- 

 tinctly prominent; mentum more or less strongly punctured 

 throughout 



' Anterior angles of head not very prominent ; tip of right outer 

 tubercle as in A. psrakensis. not b^nt outwards (fig. 33) 

 Anterior angles of head more prominent; tip of right outer 

 I tubercle bent somewhat abruptly outwards 



A. wallacei, pp. 228 & 286. 



A. perakensis, pp. 229 & 287. 



A. imsMeri, pp 229 & 287. 

 A . illegalis, pp. 230 & 287. 



