236 NEOTROPICAL PSELAPHIDAE 



Clypeus with apical margin rounded 7 



4. Antennae short and thick, segments not twice as long as wide, VIII 



and IX quadrate, X slightly transverse; 2.05 mm spathulatus 



Antennae elongate and slender, segments III to VII at least three times 

 as long as wide, VIII twice as long as wide, IX and X ovoidal 5 



5. First antennal segment strongly dilated, subcircular in dorsal outline 



and deeply concave in mesio-apical half 6 



First antennal segment with mesio-apical angle obliquely prolonged, 

 with the prolonged point recurved bidenticulatus 



6. Second antennal segment strongly globose; 1.4-1.7 mm caudatus 



Second antennal segment elongate-cylindrical; 2.3 mm divergens 



7. Antennal segments III-VII elongate but less than twice as long as 



wide, VIII quadrate, IX briefly oval ; 2 mm clypeatus 



Antennal segments III quadrate; IV slightly smaller and transverse, 

 V-VIII quadrate; 1.2-1.3 mm naso 



8. Clypeus bifid at apex ; 2.2 mm bifurcatus 



Clypeus subtruncate at apex, not bifid; 2.15 mm nasutus 



To this relatively large fifth group must be added sublyratus Reitter, 

 described on both male and female. This species is easily recognized by the 

 cephalic architecture. Sublyratus has a more triangular outline of the head 

 than any other species. The head is as long, from clypeal apex to occiput, as 

 wide if the eyes are not included ; or two-fifths wider than long if the eyes are 

 included. The clypeo- frontal area is in the form of a rounded-triangular plate 

 which is longer from apex to interantennal line than the rest of the head from 

 interantennal line to occiput. In addition the first antennal segment is as ab- 

 normal as the same segment of many males in the genus, being cordate in dorsal 

 outline, as wide apically as half the clypeal width, with the subcylindrical sec- 

 ond segment articulated in a slight median notch of its apical margin. I am 

 unable to place the species in the key as I am ignorant of the shape of the thorax. 



Group VI 



There is only one species at present in this group, demoniacus Raffray, 

 based on a single male specimen, 1.5 mm. long, with unique cephalic architec- 

 ture. The sides of the head are evenly, strongly arcuate, with the eyes placed 

 at the lowest part of the arc and not projecting much beyond a line drawn 

 through the antennal tubercle and tempora on each side; this outline is ap- 

 proached in other species but the tempora are everted and sharply, obliquely 

 truncate behind each eye so that the apical corner of each tempora is in the 

 form of a cusp; between the eyes the vertex is broadly excavated, limited 

 laterally by a double carina. 



The species of Syrbatus may be listed as follows: 



I 

 antennator (Reitter). 1888. Blumenau, Brazil. (Arthmius) 



