188 NEOTROPICAL PSELAPHIDAE 



On the other hand the swollen maxillary palpi and long conical, spiniform 

 horn of euspinifrons appear to separate the fifteenth group of the genus in a 

 qualitative sense. In the following treatment of the species, therefore, the 

 reliable grouping of Raff ray is divided into two subgeneric aggregates: 



Subgenus Decarthron s.s. (Brendel, 1865) 



Groups I to XIV inclusive of Raffray, 1904. Characterized by a simple 

 front, either declivous from interantennal baseline to apical clypeal margin, 

 or truncate and declivous, or produced as a truncated triangle between inter- 

 antennal baseline and then declivous. Front never produced into an anteriorly- 

 directed, long, cylindrical, spiniform horn between antennae. 



Although some of the species of this subgenus have simple intermediate 

 femora, the insignia of the majority are found in the abnormal intermediate 

 femora. The femur may be considered as a subfusiform segment of the leg, 

 having four faces and two ends: dorsal face, ventral face, anterior face, 

 posterior face, basal end (articulating with the trochanter) and apical or distal 

 end (articulating with the tibia). The apical end is usually subtruncate and 

 may be gradually narrowed or abruptly narrowed and pedunculate. The basal 

 end is almost always simply and acutely narrowed. The dorsal face of the 

 male femur, when modified, is greatly swollen (inflated or tumid) and presents 

 many different outlines but is usually triangular with the highest point of the 

 tumidity forming the apex of an obtuse angle near the middle third of the 

 femoral length. This swelling is usually excavated and the excavation almost 

 infinitely varies between species and within the species population. Usually the 

 excavation is a deep, broad fossa with glabrous floor but it may be a very narrow 

 sinuate or arcuate sulcus involving the posterior face as well. The excavation 

 often has the floor secondarily modified by thin lamellae or carinae or teeth or 

 spines. The outline of the excavation has two ends, an apical and a basal end. 

 The basal end often has the edge ornamented by a single spine or tooth which 

 points apically ; this spine may point dorsally or there may be two basal spines. 

 The apical end very seldom carries a spine or tooth, but it may do so and the 

 tooth may point basally and be straight or recurved. 



In this first subgenus, keys to the species are given in those groups holding 

 hitherto undescribed species (VI and VIII). Before passing to these matters, I 

 should like to give a brief note in regard to Decarthron tropicum Fletcher 

 (Group XI). This species was described on nineteen specimens collected at light 

 at night on December 19, 1926, at Vera Cruz, Vera Cruz, Mexico. I have four 

 males of this species collected on August 24, 1936, at light at night by Dr. 

 Charles Seevers at Villa Juarez, Tamaulipas, Mexico. My specimens extend the 

 northward range of tropicum to near the northward end of the coastal extension 

 of the tropical rain forest. I have compared my males with a male paratype 

 of tropicum (USNM No. 44599) and am satisfied that they are conspecific. 

 They may represent a more northern race of tropicum since the oval impression 

 of the anterior femora is lightly punctulate-granulate in comparison with the 

 same area of the paratype and the depression of the intermediate femora is a 



