Genera and Species of Coleoptera. 127 



Omolipus [Helopidse]. 



Head transverse, vertical, sulcated in front. Antennae short, gradually 

 increasing in thickness, the two basal joints small, the third longest, 

 the fourth to the seventh obconical and decreasing in length, the last 

 four subnioniliform, compressed. Eyes transverse, partially divided in 

 front. Labrum rounded anteriorly and ciliated. Mandibles bidentate 

 at the apex. Maxillary palpi securiform ; the labial approximate at 

 the base, with the terminal joint triangular. Maxillary lobes small, the 

 inner strongly hooked. Labium transverse. Mentum subtriangular, 

 truncate at the base, carinated in the middle. Prothorax convex, rounded 

 in front and at the sides, closely applied to the elytra, its parapleural 

 distinct. Scutellum small, triangular. Elytra connate, ovate, convex. 

 No wings. Legs stout ; anterior coxae globular, not contiguous ; tibiae 

 straight, unarmed; tarsi short, all the joints except the last dilated. 

 Prosternum wedge-shaped, produced, with a deep central impression ; 

 mesosternum notched for the reception of the prosternum. 



In characterizing (Edemutes (ante, p. 51), the semilunar, sulcated 

 anterior portion of the head was described as the epistome, and M. 

 Lacordaire appears to have done the same in his description of Splue- 

 rotus *. The real epistome, however, is inserted beneath the anterior 

 border, and in Sphcerotus curvipes is completely hidden by it ; but, on 

 the other hand, it is almost entirely exposed in another common 

 species, Sphcerotus gravidus. In Omoliptus (at least in the species 

 described below ; for the character scarcely seems to be of generic 

 value), the labrum, which is rather strongly developed, also appears 

 to be inserted directly beneath the anterior border of the head, and 

 the epistome is therefore not apparent. The nearest affinity of Omo- 

 lipus is probably Misolampus, from, which, among other characters, 

 the presence of a very distinct scutellum will at once distinguish it. 

 This genus is another exception to the absence of the hook on the 

 internal maxillary lobe, a character which at one time was supposed 

 to distinguish the Helopidse from the Tenebrionidse. Another excep- 

 tional character is the approximation of the base of the labial palpi, 

 which are inserted in front of the broadly transverse, membranous 

 lower lip. 



Omolipus corvus. (PI. VI. fig. 9.) 



O. ater, nitidus ; elytris punctato-impressis ; antennis tarsisque pallidi- 



oribus. 

 Hab. Australia (Melbourne). 



Deep glossy black ; head and prothorax very minutely punctured ; 



elytra narrower than the prothorax, each with about nine rows of deeply 



* Gen. des Coleopt. v. p. 446. 



