i 4 o AMERICAN SPIDERS 



It sits on a low elevation that strongly suggests the segment of an 

 ordinary spinneret. 



Hypochilus shows a greater difference from the tarantulas in its 

 habits of life than in its physical features. Whereas no tarantula 

 has become a confirmed aerial cobweb spider, the hypochilids and 

 a great many other true spiders have. It is quite possible that spiders 

 resembling the hypochilids were the first to break away from the 

 conservative tarantulas, and that Hypochilus thorelli is a modern 

 representative of an ancient group that gave rise to all true spiders. 



Hypochilus has a very restricted range. It is found in the can- 

 yons of the mountains of the southeastern United States, where it is 

 quite abundant at elevations from one to about five thousand feet, 

 and especially so in the Great Smoky, the Nantahala, and the south- 

 ern half of the Blue Ridge Mountains. It prefers dark situations 

 under overhanging rocks, and natural arches in forested areas near 

 streams. Its webs conspicuous objects even from a distance are 

 often found close together under the rock ledges. They are shaped 

 like lampshades with the top pressed against the overhanging sur- 

 face, and consist of a very heavy mesh of cribellate threads over a 

 basis of dry silken lines. 



The spider hangs underneath this net with its long legs touching 

 the sides of the aerial portion. It resembles most closely the true 

 spiders of the family Pholcidae, and is remarkable for the great 

 length of its banded legs. Hypochilus does not seem to have the 

 power of autotomy, and its legs do not break off at a point weak- 

 ened and predetermined for this purpose, as in other spiders. The 

 males, which mature in the fall, differ little from their dull, yellowish 

 mates. The male palpus is of very generalized design, and is pro- 

 vided with a conductor of the embolus as in the atypical tarantulas 

 and most true spiders. The epigynum of the female is quite simple 

 and presents no external openings. In the internal epigynum are 

 four receptacles a feature shared by the atypical tarantulas and 

 some of the most primitive true spiders. 



THE FILISTATIDS 



One of the very common house spiders of the southern Ameri- 

 can states is Filistata hibernalis, a large animal whose webs are often 

 prominently outlined on the outside walls of buildings. This spider 

 hides in a crevice during the day, and at night comes out to spin 



