334 NEOTROPICAL PSELAPHIDAE 



Third palpomere much longer than wide, gradually wider to apex 

 which is obliquely truncate ; fourth palpomere not so regularly sym- 

 metrical, slightly cultriform or knife-shaped, with external face sub- 

 rectilinear, internal face suboblique and slightly thicker at obtuse 

 basal angle; 1.54 mm.; Paraguay rugicornis 



longipes Raffray. 1904. Matto Grosso, Brazil. Genotype. 

 rugicornis Raffray. 1917. Asuncion, Paraguay. 



CERCOCEROIDES (Raffray, 1896) 



This genus at present holds six species, all residents of the South American 

 rain forest, with the swampy jungle of Matto Grosso appearing to be the center 

 of dispersal with four species. 



It is hamotine in form, allied to the subgenus Hamotus in major structural 

 features of head, pronotum, elytra, and tergites. The maxillary palpi are re- 

 markably similar to Cercoceropsis, while the metastemum is diversely tuber- 

 culate in the male sex and this latter character is fully utilized in the following 

 key to species: 



Metasternum with at least one pair of recurved or otherwise modified 

 tubercles, and the metastemum always medianly and longitudinally 

 sulcate or concave Males 4 



Metastemum not tuberculate Females 2 



2. Metasternum medianly, longitudinally impressed 3 



Metasternum simple, slightly elevated and not longitudinally im- 

 pressed ; 2.4 mm simplex Female 



3. Known from Matto Grosso ; 2.3 mm germaini Female 



Known from Paraguay; 2.3 mm.; head larger and less narrowed an- 

 teriorly; eleventh antennomere of same length (as long as three 

 preceding united in my material) , but thicker and more rounded on 



external face; fourth palpomere longer and more slender 



laticeps Female 



4. Ill slightly obconical, slightly longer than wide; IV and V quadrate; 



VI-VIII transverse 6 



Antennae not as above 5 



5. Ill, IV, V longer than wide; VI quadrate; VII and VIII transverse; 



metasternum very deeply and very broadly concave, with a very 

 strong, acute, compressed and recurved tubercle adjacent to each 



posterior coxa; Venezuela; 2.6 mm pectoralis Male 



Not known north of Paraguay river basin; III much longer than wide; 

 IV-VII quadrate; VIII slightly transverse; metasternum broadly 

 concave, with a microtubercle each side, this tubercle being acute, 

 recurved or hook-shaped; 2.5 mm tuberculatus Male 



6. Metasternum medianly narrowly sulcate, with a strong hook-shaped 



process each side; stemites strongly impressed longitudinally; 2.3 

 mm germaini Male 



