304 NORMAN E. M'INDOO. 



THE SPECIES STUDIED. 



Two species of spiders permanently live in the Mitchell caves. 

 One, Troglohyphantes (Willibalda) cavernicola Keyserling, a 

 linyphid 1 is a true cave form; the other, Meta menardi Latreille, 

 is an epeiriclicl and also lives outside of caves. According to 

 Emerton (1902, 190-) the latter arachnid "lives in caves and simi- 

 lar cool and shady places in various parts of this country and 

 also in Europe." 



Banta (1907, 65) reports Erigone infer nalis Key. from the 

 Twin Cave at Mitchell, Ind. I have been unable to find it 

 here, but have taken it in Mayfield's Cave at Bloomington, Ind. 



Troglohyphantes has been observed in detail in order to get 

 as far as possible the life history of a typical cave spider. The 

 distribution, food and results of the experiments of Meta are 

 given in order to show how an outside form is able to adapt 

 itself to a subterranean life. All notes unless otherwise stated 

 refer to Troglohyphantes. The numbers in quotation marks 

 refer to localities in the caves (see maps, pages 321 and 323). 



In Troglohyphantes there are all degrees of differences in 

 coloration, and in the degeneration of the eyes. The abdomen 

 varies in color from black, dark brown, light to white. The 

 cephalothorax varies from dark, pinkish, light to a white color. 

 The most common combination of colors is a light brown ab- 

 domen with a pinkish cephalothorax. The adult females range 

 in length (cephalothorax and abdomen) from 2.4 mm. to 3.7 mm., 

 while the adult males vary from 2.2 mm. to 3 mm. 



In the adults the eyes range from eight in number, each with 

 a maximum size of 0.036 mm. in diameter to no external signs 

 of eyes. I have not seen Keyserling's description, but from his 

 figure, which Packard 2 has copied, the eyes are small, and the 

 front middle ones extremely minute. 



PHYSICAL ENVIRONMENT. 



These spiders are found only in total darkness, where the 

 atmosphere is saturated, and in places suitable for the construc- 

 tion of snares. They are never found where the walls are per- 

 pendicular with water covering the entire floor; nor are they 



'Banks, '06, classification. 

 2 i888, Plate XV., Fig. 32. 



