IQ14.] F. H. GravEIvY : An Account of the Oriental Passalidae. 191 



usually stronger at the sides than above ; and when the side-grooves are broad the 

 punctures are drawn out laterally so that they come to form a series of short transverse 

 secondary grooves within the primary grooves. These secondary grooves are not of 

 absolutely constant form in all specimens of a single species; but they are sufficiently 

 constant to be of great taxonomic value. I have rarely, however, found the slight 

 variations that occur in the distinctness of the punctures of the dorsal grooves of any 

 value whatever, though Kuwert seems to have placed great faith in them. Another 

 character to which Kuwert attached greater importance than it deserved, was the 

 puncturing of the sides of the elytra of different species of the genus Aceraius. This 

 puncturing, unless it occurs on the eighth rib (counting the innermost rib as the first) , 

 as well as on the seventh and ninth, is by no means constant in extent in each species ; 

 and although it is often most useful (especially in worn specimens) as a confirmatory 

 character, as a primary character it is apt to prove misleading. The presence of 

 hair on the sides of the elytra seems to be a satisfactory character by which to 

 distinguish two genera, Aceraius and Trichostigmus, from their respective allies. 



3. THE CLASSIFICATION OF INDO-AUSTRALIAN PASSALIDAE. 



The preceding account of the external morphology of Oriental Passalidae has 

 already indicated that all species which come within the scope of the present paper 

 fall into one or other of two widely different sections of the family. The first of 

 these sections includes the Aulacocyclinae of Kuwert, together with the genera 

 Auritulus and Cylindrocaulus , whose affinities with the Aulacocycline genus Ceracupes 

 have been established by Arrow (1907, p. 446). Kuwert, who overlooked the 

 only known species of the genus Auritulits, defined the Aulacocyclinae only accord- 

 ing to the apparent structure of the pro sternum relative to the coxae of the 

 first pair of legs, excluding the genus Cylindrocaulus which he placed next to a Mexi- 

 can form. The part of the prosternum between the coxae of members of the second 

 section of Oriental Passalidae does not, unless the coxae are dug out from their 

 sockets, appear as a lamina. Consequently it may be concluded that the ''strongly 

 elevated lamina ' ' , that Arrow mentions as separating the front coxae of Cylindrocaulus 

 bucerus from one another, is an exaggerated form of the keel which always extends 

 along the middle-line of the central part of the prosternum of the Aulacocyclinae. 

 Assuming this to be the case, the two sections into which the Oriental Passalidae are 

 primarily divided may be distinguished by the following characteristics' : — 



' Although the present paper does not deal with internal structure, reference must be made here to 

 Sharp and Muir's works on "The Comparative Anatomy of the Male Genital Tube in Coleoptera " 

 (Trans. Ent. Soc. London, 1912, pp. 477-642, pi. xlii-lxxviii, Passalidae, pp. 570-580, pi. xliv, 

 figs. ii-i3rt). These investigators found that in representatives of the genus Aitlacocycliis, the only 

 genus of Aulacocyclinae they examined, -'the basal-piece and the lateral lobes form one piece, either 

 by consoHdation or the supression of the basal-piece," whereas in representatives of the genera 

 Gnaphalocnemis { = Eriocnemis) , Labienus and Protomococlus (Gnaphalocneminae), Leptanlax (I/Cptaula- 

 cinae), and of the American genera Procu/ws and Neleus '-the tegmen consists of two distinct pieces, 

 the basal piece and the lateral lobes." 



