364 NEOTROPICAL PSELAPHIDAE 



Table V {Continued) 

 SELECTED ALTITUDE RECORDS OF PSELAPHIDAE 



Species Elevation Country Source 



in feet 



Reichenbachia sallaei 4000- 5000 Cerro Zunil, Guatemala Sharp 



2000- 3000 Chiriqui, Panama Sharp 



Reichenbachia intacta 1000 Cahabon, Guatemala Sharp 



Thesium impressifrons 4000- 5000 Cerro Zunil, Guatemala Sharp 



Trimiodina concolor 8500-10000 Totonicapam, Guatemala Sharp 



Rhexius optatus 4000- 6000 Chiriqui, Panama Sharp 



Eurhexius vestitus 2000- 3000 Chiriqui, Panama Sharp 



Eurhexius parviceps 8000 Chiriqui, Panama Sharp 



Eurhexius ventralis 3000- 4000 Chiriqui, Panama Sharp 



Eurhexius trimiodes 8500-10500 Totonicapam, Guatemala Sharp 



Endytocera vestita 2500- 4000 Chiriqui, Panama Sharp 



Endytocera cognata 800- 1500 Bugaba, Panama Sharp 



I have used here the records of Sharp's ancient work. Although his de- 

 scriptions are not complete, his locality data are much better than the more 

 recent work of Raffray. From this table we find the greatest elevation at- 

 tained by neotropical pselaphids to be Totonicapam, Guatemala (Eurhexius 

 trimiodes) at 10,500 feet, and the greatest known vertical range that of 

 Hamotus setipes, from 800 to 4000 feet in Panama. The few data make pre- 

 diction rather hazardous but the situation in Eurhexius is suggestive, with 

 vestitus at 2000-3000 in northern Panama, ventralis at 3000-4000 in the same 

 forest, parviceps at 8000 in the same forest extension, and northwards trimiodes 

 at 8500-10500 in Guatemala. There are many species described from "Haute- 

 Bolivie, Yuracaris" which suggest considerable altitudes, and a third critical 

 area for study would be the Bolivian Andes from the northeastern corner up the 

 Madeira drainage to tree-line. This should throw much light on altitude strati- 

 fication from the Amazon floor to the limit of penetration; this compared with 

 a similar transect in the Panamanian Chiriqui, Guatemala, and Central Mexico 

 would be especially desirable. Of course these remarks refer to the free-living 

 species. The symphiles, and to a less extent the synoeketes, live in the relatively 

 stable, dark, humid nest of their host and their distribution becomes the host's 

 distribution. In such cases the oxygen available and the barometric pressure 

 would be the two influences varying with altitude, while food, shelter, lack of 

 light and relative humidity would remain more or less constant; temperature, 

 especially nocturnal temperatures, in and out of the ant and termite nest in a 

 restricted altitude range have not been sufficiently studied in this respect. 

 Some information is at hand on one genus of symphiles: Fustiger insignis and 

 schmidti occur at 6000 feet in Costa Rica, while Fustiger veracruzensis occurs 

 at 5500-5000 in Vera Cruz, Mexico. 



Since pselaphids are poikilothermal this problem of vertical distribution 

 probably has a profound effect upon their distribution and is taken into ac- 

 count later in the discussion of taxonomic density. At least four zones are 

 recognized for the Andes (Chapman, 1933; Cutright, 1940): tropical (sea 

 level to 3,500-5,000 feet); subtropical (3,500-5,000 to 8,000-9,000 feet); 



