228 NEOTROPICAL PSELAPHIDAE 



Frontal incisure less deep, less wide, more ogival-triangular, prolonged 

 posteriorly in a sulcus which disappears on the vertex; clypeus tri- 

 angularly gibbous; trochanters simple; metasternum with short 

 setae; 1.7-1.9 mm melanocephalus 



15. Frontal incisure transverse, medianly angulate, with long setae, and a 



slender carina disappearing posteriorly on the vertex; epistome 

 (clypeus) with a strong, erect, triangular, pointed horn which is 



densely pubescent; trochanters simple; 2.5 mm ciliatus 



Frontal incisure very wide, medianly circular and in the center of this 

 incisure is a rudimentary tubercle or swelling; front and clypeus 

 separated by a deep, slightly transverse excavation; clypeus with a 

 strong, thick, triangular, flattened and slightly recurved horn; tro- 

 chanters simple ; 1.8 mm rufipes 



16. Anterior part of vertex with a slender median carina; antennae elon- 



gate, slender with segments at least twice as long as wide ; front with 



two transverse, vaguely limited foveae carinatus 



Vertex without carina, either medianly excavated or simply convex. . 17 



17. Vertex with a median fovea, and lateral margins of head each with a 



small tooth or cusp germaini 



Vertex with or without a median fovea or impression but the sides of 

 the head not toothed 18 



18. Vertex with a median foveaform depression; head slightly transverse 



with antennal tubercles slightly prominent laterally, large, flattened, 



obliquely cut and subcarinated at summit auriculatus 



Vertex with neither a median carina nor fovea 19 



19. Front with an entire, transverse impression just posterior of a hypo- 



thetical line passing through the antennal tubercles, .drcumscriptus 

 Front without a transverse post-tubercular impression ; head with four 

 free foveae, of which the posterior pair lie between the eyes and are 

 punctiform, relatively small and shallow, while the anterior pair are 

 slightly oblong and obliquely placed between the antennal tubercles 

 elevatus 



Key to the Species of Group VIII 



Six sternites fully visible (Males) 2 



Five sternites fully visible (Females) 7 



2. Head quadrate (that is, the width of the head not including the eyes, 

 is equal to the head length), with tempora more rounded than the 

 antennal tubercles; vertex perfectly simple from occiput to eyes 

 with the usual pair of vertexal foveae ; anterior of the eyes the vertex 

 is transversely, narrowly impressed in an entire striaform line which 

 broadens and deepens at middle, this median depression in reality 



foiTned by a pair of foveae; 2.4 mm jauveli 



Head more or less transverse (that is, the width of the head not in- 

 cluding the eyes, is greater than the head length) 3 



