ARENEIDA THERIDIID^E. 63 



Porrhomma myops Simon, known from a cave in southern France 

 and another cave in Ireland, Carpenter (1895, 59) thinks, is identical 

 with Packard's Willibaldi incerta. Certainly, then, a close similarity 

 exists. 



Phanetta subterranea (Emerton). 



Linyphia subterranea EMERTON, Am. Nat., ix, 1875, 276, 279, pi. 1, figs. 29-31 (Carter 



Caves, Kentucky, and Wyandotte Cave); Mem. Nat. Acad. Sci., iv, 1888, 16, 



56, 57, pi. xv, figs. 29, 30, 31. 

 Phanetta subterranea KEYSERLING, DieSpinn. Am., Therid., n, 125, fig. 205. BLATCH- 



LEY, Rep. Tnd. Geol. Surv., xxi, 1896, 204 (Wyandotte Cave). MARX, Proc. 



U. S. Nat. Mus., xil, 1889, 531. 



Very abundant in all parts of the cave. The most abundant arachnid. 

 It is invariably found under stones or debris where there is considerable 

 moisture. It sometimes has a few short strands of web. It is often 

 attracted to decaying organic matter and is nearly always associated 

 with the thysanurans. It is quite possible that the latter are attracted 

 to the organic matter and that the spiders are attracted by the thysan- 

 urans. It is quite sluggish in its movement, except when springing 

 upon its prey. In February, 1904, I turned over a damp rock at "23," 

 on the under side of which were dozens of thysanurans and two of these 

 spiders. The larger spider jumped towards a thysanuran, which sprang 

 away and escaped, but with a second quick movement the spider caught 

 another, clutching it firmly, and did not release its hold even when 

 pursued, until it was picked up. This species probably feeds almost 

 entirely upon the thysanurans, but I found one which appeared to be 

 eating at a bit of decayed cheese. A myriapod found entangled by a 

 single strand of web of this spider may have served as food. This spider 

 often forms a small web of a few short, irregularly arranged strands, 

 which it attaches to the debris under which it lives and to the rock or 

 soil beneath. 



The negative phototropism of this species is very pronounced. Indi- 

 viduals placed in short bottles in a dark room into which a little light 

 was admitted remained in the end of the bottle away from the light. 

 One experimented with in the cave behaved as follows: It moved 

 actively but irregularly for a moment after the stone was removed from 

 over it. Then when bright light was thrown upon it, went directly 

 away from the light. It was made to turn back and forth three times 

 by changing the direction from which the rays of light struck it, turning 

 squarely from the light in each case. After having been molested so 

 much that it seemed bewildered, it moved rather irregularly and with- 

 out definite direction until it accidentally ( ?) went away from the light, 

 when it kept moving in that direction. During all this time it was 



