284 NEOTROPICAL PSELAPHIDAE 



Antennae of eleven segments BIBRAX 



Antennae with less than eleven segments 2 



2. Antennae of six segments 3 



Antennae of five segments 4 



3. Antennal segment I convex on dorsal face, concave on ventral face, 



with the face margined for its entire length by a thin, denticulated 



lamella LISTRIOPHORUS 



Antennal segment I cylindrical, gradually thickened and slightly 

 sinuate to apex GONIACERUS 



4. Antennal segment I strongly elongate, slightly sulcate mesially; II 



subquadrate; III oblong in females and obconical in males; IV 

 quadrate; V oblong-cylindrical, with an acute apex; wide abdominal 

 margins limited externally and internally by carinae; known only 



from Paraguay GONIACEROIDES 



Antennae not as described ; abdominal margins narrower, in the form 

 of a flattened, narrow, sharply cut lamina ; known only from Brazil 5 



5. Antennal segment I elongate, deeply sulcate on dorsal face, with the 



internal face having a thin denticulated marginal lamina as in 

 Ldstriophorus ; II slightly transverse; III cylindrical; IV slightly 

 longer than wide, cylindrical; V ovoidal-acuminate. .GONIASTES 

 Antennal segment I elongate, convex on dorsal face, concave on ventral 

 face, slightly sinuate; II small, transversely triangular; III large, 

 strongly obconical and with the ventral face excavated; IV trans- 

 verse, slightly wider at apex than third; V slightly narrower than 

 fourth, slightly longer than wide ADROCERUS 



BIBRAX (Fletcher, 1927) 



This monotypic genus has its nearest apparent ally in the Ethiopian Ogmo- 

 cerus because of its eleven-segmented antennae and strong abdominal margins. 

 Its aspect is similar to the Metopiini with non-spinose pronotum (Metopiellus, 

 Metopiosoma, Barrometopia) . Males have the fourth stemite medianly flattened 

 and shining; fifth with a large transverse depression; sixth (last) stemite with 

 a deep circular apical fovea. Females with sternites simply, evenly convex. Eyes 

 composed of a single facet. Maxillary palpi four-segmented. 



bradleyi Fletcher, 1927. Barro Colorado Island, Gatun Lake, Panama 

 Canal Zone. Genotype. 



LISTRIOPHORUS (Schaufuss, 1872) 



This is a monotypic genus with three-segmented maxillary palpi, and bril- 

 liantly shining integuments. The six-segmented antennae separate it from other 

 neotropical aggregates with the exception of Goniacerus, from which it is 

 quickly diagnosed by the remarkable first antennal segment and an entirely 

 different integumental structure. 



felix Schaufuss. 1872. Mexico. Genotype. 



