I9I4-] 



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



323 



/At least 34 mm. long; very variable in structure; right outer 

 tubercle simply pointed in profile in unworn specimens ; scars 

 J on mesosternum almost always distinct 



\ At most 32 mm. long; less variable; right outer tubercle 

 slightly truncate in profile in perfectly unworn specimens ; 

 V scars on mesosternum obsolete 



I" Posterior part of tenth and whole of eighth ribs of elytra un- 

 14'' punctured 



( Seventh to tenth ribs of elytra (inclusive)punctured throughout 



/Convexity of upper margin of left mandible very high and 



j strongly curved — usually much higher than in any other 



species; left outer tubercle rather slender; right outer tuber- 



15 ' cle more or less truncate in profile 



Convexity of upper margin of left mandible moderately high 

 and strongly curved ; left outer tubercle somewhat stouter ; 

 Vright outer tubercle variable 



( Free portion of left outer tubercle distinctly longer than broad ; 

 j(j j right outer tubercle often very broadly bifid in profile 



\ Free portion of left outer tubercle more or less square ; right 

 I outer tubercle not very broadly bifid in profile . . 

 ( Right outer tubercle distinctly bifid in profile 

 ( Right outer tubercle at most imperfectly bifid in profile 

 •'Anterior lower tooth of left mandible very large, as in all 

 preceding species of the genus, much larger than that of left 

 mandible; posterior part of tenth and whole of eighth ribs of 

 i8( elytra unpunctured 



Anterior lower tooth of left mandible scarcely larger than that 

 of right; seventh to tenth ribs of elytra (inclusive) somewhat 

 sparsely punctured throughout 



Genus Macrolinus, Kaup. 



( Inner tubercles, and anterior part or whole of frontal ridges, 



i obsolete 



] Frontal ridges complete and well developed, inner tubercles 



( more or less distinct 



/'Apex of central tubercle approximately rectangular in profile, 



I directed upwards, not overhanging . . 



\ Apex of central tubercle acute, directed forwards, somewhat 



\^overhanging . . 



/Ridge joining inner tubercles separated from anterior margin 



of head throughout its whole length by a more or less concave 

 3 surface 



Ridge joining inner tubercles closely approximated to anterior 

 [margin of head either in middle or throughout . . 

 ( Lateral grooves of elytra narrow, punctures normal 

 \ Lateral grooves of elytra broai, punctures transversely linear M. sikkiimnsis, pp. 



A. laevimargo ,^ pp. 238 & 291. 



A. pilifer, pp. 235 & 291. 



15. 



A. borneanus,pp. 238 & 292. 



A.alutaceosfermis ,pp. 236 & 291. 



16. 



.4. helfen, pp. 238 & 292. 



.4. assammsis, pp. 337 & 292. 

 A. himalayensis, pp. 236 & 292. 



, pp. 240 & 293. 



.4. aequidens, pp. 240 & 293. 



M. urus, p. 294. 



M. duivenbodei, p. 294. 



6. 



5- 



243 & 294. 



^ Or the slightly larger A. perakensis (pp. 229 & 287) in which the upper margin of the left 

 mandible is very variable and may be indistinguishable from that typical of the section of the genus to 

 which A . laevimargo belongs. 



