DIPNEUMONES. 



649 



genus Dysdera there are six ocelli, of which four lie in the front 

 row ; the cephalothorax is small, long, oval, and the fii'st pair 

 of leo-s are the longest. The species dwell in silken tubes, 

 under stones or in crevices. D. interrita Hentz is a New 

 England species. In Drassus there are eight ocelli, and the 

 hiudermost pair of feet are the longest. 



Clubione includes those species which have eight ocelli, the 

 four hinder ones, with the two outer ones on the front row, 

 forming almost a semicircle ; the fore legs are the longest. 

 They construct under the bark of trees, under leaves or be- 

 neath stones, tubes of very white silk, from which they make 

 nocturnal expeditions for food. C. tranquilla Hentz is com- 

 mon in the United States. C. medicinalis Walkenaer has been 

 used as a vesicant. The 

 Water spider of Europe, 

 Argyroneta aquatica Linn., 

 lives beneath the water, 

 where it makes its nest and 

 cocoon, which is filled with 

 air. 



The genus Tegenaria has 

 the ocelli arranged in two 

 slightly curved rows, the 

 third pair of feet are shorter 

 than the others, and the ab- 

 domen is oval. The species 

 are " sedentaiy, making in Fig- 62S. 



obscure corners a horizontal web, at the upper part of which 

 is a tubular habitation, where the spider remains motionless 

 till some insect be entangled in the threads." (Hentz.) 

 T. medicinalis Hentz is "pale brown, turning to bluish black ; 

 cephalothorax with a blackish band on each side ; abdomen 

 varied with black, or plumbeous and brown ; feet varied with 

 blackish." It " is found in every cellar or dark place in the 

 country. For some time the use of its web as a narcotic, in 

 cases of fever, was recommended by many physicians." 

 (Hentz.) Fig. 628 (enlarged) represents T. atrica, a European 

 species. 



Filistata is a closely allied genus. F. hibemalis Hentz 



