176 NEOTROPICAL PSELAPHIDAE 



Antennae with segments V and VI subcylindrical, distinctly longer 



than wide quadraticeps 



(1.1 mm.; antennal segments I short, quadrate; 

 II elongate-ovate ; III-VII subcylindrical ; VIII 

 quadrate; IX larger and quadrate; X twice as 

 large as ninth; XI briefly ovate) 



Antennae with segments V and VI moniliform 2 



2. First tergite with the two basal, discal carinae divergent, approximate, 



their apical ends separated by about the distance between the two 

 sutural striae of the elytra, these striae of the first tergite distinct, 



about one-third of tergite length bisulciceps 



(1.1 mm.; close to quadraticeps) 

 First tergite with the two basal, discal carinae very short and in- 

 conspicuous 3 



3. Antennae segments VII and VIII moniliform and of same size; IX 



transverse, slightly wider than eighth; X twice as large as ninth, 



subquadrate-transverse. Metastemum flattened mniszechi 



(1.3 mm. close to nigra) 



Antennae with segment VII moniliform, VIII hardly larger than 



seventh, transverse; IX slightly larger, transverse, slightly acute 



internally ; X twice as large as IX, slightly transverse. Metasternum 



posteriorly and widely, subtriangularly impressed nigra 



(1.4 mm. close to mniszechi) 



quadraticeps Raffray. 1904. Bolivia. Genotype. 

 bisulciceps RafTray. 1904. Bolivia. 

 mniszechi Raffray. 1904. Colombia. 

 nigra Raffray. 1904. Venezuela. 



XYBARIS (Reitter, 1882) 



This is a genus of pselaphids confined to the neotropics. It contains seven 

 species from Brazil and one from the Panama Canal Zone. These eight species 

 all agree in the following: (1) normal maxillary palpi, (2) a median longi- 

 tudinal carina on the ventral surface of the head, (3) base of pronotum with 

 a lateral fovea each side and a median fovea, (4) two or four well formed 

 foveae at the base of each elytron, (5) the dorsal elytral stria represented 

 by a very faint intrahumeral impression, (6) a narrow abdominal margin, 

 (7) mesostemum produced posteriorly between the mesothoracic coxae as a 

 distinct and truncate plate, (8) metathoracic coxae not conical; and distant 

 from each other, (9) five visible tergites and sternites, the true first sternite 

 invisible between the posterior coxae. These characters separate the members 

 of the genus from all other brachyglutine aggregates. 



The sexes may be readily distinguished. The males have the second tar- 

 somere of the anterior tarsi laterally dilated and slightly flattened dorso- 

 ventrally and with a conspicuous brush of setae on this flattened ventral sur- 



