1918.] F. H. Geavely : Passalidae of the World. 2& 



tubercle and frontal ridges, which may be united and never have a roughened area between 

 them, and its prothorax which is strongly punctured in and close round the scars. 



Genus OILEUS, Kaup, 1869, p. 3. 



Incl. Coniger, Zang, 1905 c ; Rimor, Kaup, 187 1 ; Rimoricus, Kuwert, 1897. 



Type, Passalus rimator, Truqui, 1857, p. 266 (see Arrow, 1907, pp. 447-449.) 

 Species of this genus appear to be much larger than are those of the last, and further- 

 have always, so far as is known, a large decumbent central tubercle with free apex, instead 

 of a feebly developed one, as well as a linear instead of an expanded clypeus. 



Oileus ridiculus (Kuwert). 

 Fig. IV, 2. 

 Rimoricus ridiculus, Kuwert, 1897, p. 287. 

 Three specimens from Guatemala. Length 34-35 mm. 



The lamellae of the antennae are extremely short, being equal to not more than two o£ 

 the immediately preceding joints in length ; the pronotum is punctured in and around 

 the scars ; the scutellum is roughened all over with obsolete punctures ; the mesosternal. 

 scars are hairy ; and the grooves of the elytra are very finely punctured. In one specimen, 

 the mesosternum is coarsely punctured. 



Oileus sargi (Kaup). 



Rimor sargii, Kaup, 1871, pp. 119-120. 



One specimen from Guatemala. Length 30 mm. 



The antennal lamellae are very long, being as long as about four of the immediately 

 preceding joints ; the pronotum is unpunctured ; the scutellum is strongly punctured in 

 the middle ; and the mesosternal scars are not hairy. 



Oileus rimator (Truqui). 



Passalus rimator, Truqui. 1857, p. 266. 



One specimen from Omilteme, Guerrero, 8,000 ft., lent by the British Museum. Length 

 37*8 mm. 



This species is closely allied to 0. sargi, from which it differs in having the clypeua 

 lightly biconvex, the anterior margin of the pronotum biconcave and the mesosternal scars- 

 hairy. 



Genus UNDULIFER, Kaup, 1869, p. 6. 



Type, Passalus incisus, Truqui, 1857, pp. 266-267. 



Undulifer incisus (Truqui). 

 Fig. IV, 3. 

 Passalus incisus, Truqui, 1857, pp. 266-267. 



One specimen from Cordova, Mexico, presented by the British Museum. Length 29 mm, 



Undulifer incisus is closely related to Oileus ridiculus and sargi. The antennae of the 



single specimen before me are broken, but from the one remaining lamella I conclude that 



