1918.] F. H. Gravely : Passalidae oj the World. 17 



The species of Taeniocerus may be identified thus : — 



The upper surface of the central tubercle about twice as long as 

 broad, flat, punctured, bordered by a very distinct horse-shoe- 

 shaped ridge which is open in front . . . . . . T. bicanthatus. p. 16. 



The upper surface of the central tubercle relatively broader as a 

 rule, less flattened, unpunctured, the marginal ridge often in- 

 distinct or absent across the middle-line behind as well as in 

 front . . . . . . . . . . 9 



C The anterior tibiae very broad . . .. .. T. 'platypus, p. 16. 



' \ The anterior tibiae slenderer . . . . . . o 



(The anterior margin of the canthus meeting the side of the head 

 at a considerable distance behind the anterior angle ; the 

 external angle of the canthus obtuse . . . . T. pygmaeus, p. 16. 



The anterior margin of the canthus meeting the side of the head 

 at a very short distance behind the anterior angle ; the 

 external angle of the canthus sharper . . . . T. bicuspis, p. 16. 



Genus AULACOCYCLUS, Kaup, 1868«, p. 4 . 

 Incl. Taeniocerus [part] +Caulifer, Kaup, 187 1 -f Tristorthus, Kuwert, 1896, p. 220. 

 Type. Passalus edentulus, MacLeay, . 826, p. 439. 



Aulacocyclus glabriusculus, Kuweit. 



Aulacocyclus glabriusculus, Kuwert, 1897, pp. 280 and 282. 



A number of specimens from Aru Island. Length 25-4-27-3 mm. 



The antennal lamellae are long and slender ; the central tubercle, which closely resem- 

 bles that of A. edentulus (fig. iii, 7), is erect at base, oblique or almost horizontal above, 

 where it is medially grooved, the apex scarcely or not at all bent downwards. The elytra! 

 grooves are shallow, and are scarcely punctured either above or below. 



Aulacocyclus perlatus, Kaup. 

 Fig. Ill, 1, p. 18. 



Aulacocyclus perlatus, Kaup, 1868a, p. 7. 



Four specimens from New Guinea, three of them being from Stephansort, Astrolabe Bay. 

 Length 19-5-2 r6 mm. 



The antennal lamellae are long and slender, as in the preceding species. The central 

 tubercle is decumbent, and more or less distinctly bent downwards at the apex. All the 

 grooves of the elytra are strongly punctured. 



Aulacocyclus parryi, Kaup. 



Aulacocyclus parryi, Kaup, 1868a, p. 8. 



Represented by specimens from Ceram, Halmaheira (Dodinga), Ternate and Singapore. 

 Length 23-2-25*3 mm. 



The antennae and elytra resemble those of the preceding species. The central tubercle 

 resembles that of A. glabriusculus and A. edentulus, but is inclined to be slightly thickened 

 on the under side just at the apex, giving it a somewhat more hooked appearance. 



.15 



