224 NEOTROPICAL PSELAPHIDAE 



Intermediate trochanters absolutely devoid of a pubescent brush; 



2.2 mm brevicollis 



10. All trochanters simple 11 



Anterior trochanters with a short apical spine; intermediate trochan- 

 ters with a slender, sharp pointed, erect, very long median spine; 



2.3 mm tibialis 



11. Anterior tibiae absolutely simple; metastemum with a deep median 



oblong fovea; first fully visible sternite with a thin, posteriorly- 

 directed ligula; 1.4 mm mancus 



Anterior tibiae abnormal 12 



12. Anterior tibiae not dilated on external face, but short and thick, with 



the internal face thicker and rounded at middle, these tibiae not 



apically sinuate ; 2.3 mm bicornis 



Anterior tibiae with different modifications 13 



13. Anterior tibiae with an abrupt, pointed dilation near the middle of 



the dorso-external face; 2 mm simplicicornis 



Anterior tibiae nearly entirely dilated on the external face, this 

 dilation slightly rounded and flattened; 1.4-1.5 mm latipes 



14. First apparent sternite (second morphological) with a median longi- 



tudinal carina near base hydropicus 



First apparent sternite (second morphological) with no median longi- 

 tudinal carina manifestus 



Key to the Species of Group VI 



Six stemites fully visible (Males) 2 



Five sternites fully visible (Females) 14 



2. Head not excavated 3 



Head variously excavated 4 



3. Margin of front between antennal bases simply concave or poster- 



iorly arcuate, with a pair of short conical approximate and anteriorly 



inclined truncated tubercles; 2.8 mm rhinoceros 



Margin of front between antennal bases biarcuate with the median 

 area, joining the arcuations, produced anteriorly into a subacute, 

 triangular extension; 2.3-2.4 mm sus 



4. Species unknown south of Panama 5 



Species unknown north of Brazil 6 



5. Lateral margin of the vertex above each eye erected into a strong but 



obtuse, slightly arcuate carina; 2.0-2.2 mm vividus 



Lateral margin of the vertex above each eye not at all carinated; 

 2 mm armatellus 



6. Head much longer than wide not including the eyes, or as long as 



wide including the eyes; lateral margins of the vertex concave or 

 sinuate, the head widening to the prominent laterally everted anten- 

 nal tubercles ; vertex broadly excavated from eyes to frontal margin, 

 this depression bearing an elongate carina in the shape of a narrow 



