322 NEOTROPICAL PSELAPHIDAE 



Head with length and width subequal, of the usual form, with long con- 

 vergent tempora. Eyes moderately prominent, median, reniform, with about 

 96 very minute facets. Vertex with three relatively large nude foveae ar- 

 ranged in a triangle: a pair placed on a line through eye centers and as near 

 each other as either is to its adjacent eye — each of these foveae lies in the 

 apical margin of a definite ovate depression, which gives a peculiarly double 

 aspect to these interocular foveae; the third fovea is median and anterior, 

 placed at the base of the narrow longitudinal sulcus separating the small 

 antennal tubercles. Front, clypeus, and labrum as in costaricensis. Ventral 

 surface of the head is flattened, with a longitudinal lateral carina each side 

 below the eye — which is an approach to the condition in alleei — and a tri- 

 angular gular fovea at middle of base. 



Maxillary palpi of usual hamotine form ; fourth palpomere with the longi- 

 tudinal sulcus of the internal face not entire, reaching to three-fourths of length, 

 slightly oblique, narrow with an expanded apical end in which is inserted 

 the very oblique palpal cone. 



Antennae short and thick; I elongate-cylindrical; II less elongate, but 

 longer than wide, smaller than first; III-VIII all transverse; IX larger, asym- 

 metrically trapezoidal, transverse, mesial face shorter than lateral face; X 

 still larger and very transverse, also asymmetrically trapezoidal; XI as long 

 as four preceding united, as wide as long, with very round apex. 



Pronotum distinctly transverse; form as in costaricensis; three pubescent 

 antebasal foveae of which the median is distinctly smaller than the lateral. 



Elytra as in costaricensis. 



Wings well developed. 



Abdomen with five visible tergites in a length ratio of 3/3/2/2/1.5 and 

 the first three strongly margined. Six simple stemites in a length ratio of 

 1/3/.8/.5/.4/.4. 



Metastemum, posterior coxae, and intennediate coxae as in alleei. 

 Posterior tibiae slightly arcuate in apical fourth, and bearing an apical spur 

 of setae. This apical spur is moderately long, very slender, strongly angulate, 

 aciculate. Tarsi as for genus. 



Named on three specimens collected by the author on Barro Colorado 

 Island, Panama Canal Zone, from decaying log mold of the forest floor. Sex not 

 determined with certainty from external anatomy. Type on July 6, 1936, at 

 Armour 7 and two paratypes on July 26, 1936, at Armour 8. Named for one 

 of the younger students of Pselaphidae, Dr. Sanderson. This species is dis- 

 tinctive in its morphology. It is typical of Raffray's fourth group and ap- 

 pears to be closest to bulbifer of Colombia from which it is quickly separated 

 on pronotal dimensions. 



Hamotus (Hamotus) castanalus new species 



Type. Measurements: Head 0.40 x 0.43 mm.; pronotum 0.47 x 0.49 mm.; 

 elytra 0.60 x 0.94 mm.; abdomen 0.74 x 0.87 mm.; total length 2.21 mm. 



Integument shining reddish-chestnut; almost impunctate save for legs 



