TYPICAL GROUP 



3195 



objects. In addition to these forms which belong to the family Dysderidce this 

 tribe contains the family Oonopidce, comprising small, slender-legged spiders, with 

 a short and high carapace, and the exotic family Caponiidce, the chief peculiarity of 

 which is the transformation of the front pair of lung sacs into tubular tracheae 

 a characteristic in which this family is unique among spiders. The Filitelarice 

 contain the family Filistatidcz and genus Filistata; the latter being represented by 

 several species, none of which are British. They are small or medium-sized 

 species, easily recognized by the aggregation of the eight eyes upon a tubercle 

 placed near the front border of the carapace and of sedentary habits, spinning an 

 extended web of white silk, in the form of an ill-defined tube. 



To the Tubitelariiz are referred a number of families, presenting great variation 

 both in structural features and instincts. The Drassidce, for instance, spin no snare, 

 but merely fabricate a silken case for themselves and young at the breeding season, 

 while others, like th&AgaUni&e, which include the house spider {Tegenaria atrica), 



WATER SPIDERS, WITH NESTS (enlarged). 



build a flat, sheet-like web, continuous at one extremity with a tubular retreat in 

 which the spider lurks. The spiders of this last group which spin these sheet-like 

 snares are furnished with three claws on each fo,ot, and long posterior spinning 

 mammillae; whereas the Drassidce and Clubionidce, which live under stones, make no 

 snare, and catch prey by chase or by lying in wait, have all the spinning mammillae 

 short, and only two claws on the feet. The above families differ from the preceding 

 tribes of Arachnomorphce in that the stigmata of the posterior pair of breathing 

 organs are not only united in the middle line to form a single aperture, but this has 

 also, as a rule, moved to the end of the abdomen in front of the spinning mammillae. 

 In two of the families, however, these apertures, although covered with a fold of 

 the skin, are distinct from each other, and have only migrated part of the distance 

 over the lower surface of the abdomen. These families, Desidce and Argyronetidce , 

 have three-clawed feet like the Agalenidce, but instead of being snare spinners, 

 fabricate a silken case to serve as a receptacle for their eggs and as a place of refuge. 

 Both have an aquatic mode of life. The first family is represented by the genus 



