GENERAL COCOONING HABITS OF SPIDERS. 157 



the bed of the stream is hollow and connected with the cavernous forma- 

 tion which characterizes the entire region. The water could be seen trick- 

 ling down through the pebbles, and, by putting the ear to the ground, it 

 could be heard dropping into the depths beneath. 



I observed that, in. the neighborhood of the place where the threaded 

 points of the stream thus sunk out of sight, numbers of little spideix 

 were running about, some of them probably seeking food, but 

 otliers appearing simply to be enjoying themselves like other 

 Brink. voun g animals at play. These spiderlings seemed to be chiefly 

 Lycosids, though some of them were probably the young of 

 Agalena naevia, and, it may be, other species. They were running over 

 the bed of the brook and hiding under the pebbles at the very spot 

 where the water sunk out of sight; and it immediately occurred to me 

 that nothing was more likely than that numbers of these spiders might 

 be, and indeed had been, caught in the falling waters and carried down 

 into the cavern underneath. 



They have sufficient vitality to endure, without much injury, such a 

 transition, but what would befall them when they reached their subter- 

 ranean prison ? Would these lost spiderlings make themselves at home 

 and proceed to adapt themselves to their new environment ? Many spiders, 

 we know, love gloomy abodes, dens in the earth and shaded spots. They 

 are nocturnal creatures, and go out at night to seek their prey. It would 

 not be so very difficult for creatures reared under these circumstances to 

 survive in total darkness, if only the means of livelihood could be found. 



But what would be the influence of environment upon these unwilling 



prisoners of the cave ? How long would it be ere change in life compelled 



a change in structure ? To what degree would that structural 



)C T S change occur? What forms are those most likely to survive 

 such a transition? What species were the ancestors of our cave 

 fauna? As far as 'known, those now extant appear to belong chiefly to 

 the Theridioids, and their habits indicate the rudimentary form of spider 

 life which is possessed by that family. Have all other species accident- 

 ally introduced into caves perished, except these delicately organized Reti- 

 telarians. Or shall we think that some species have gradually been trans- 

 formed by the influence of their strange new life into those peculiar forms 

 which now inhabit our caves? 



Judging from the well known habits of surface species, I would have 



expected and predicted that the prevailing fauna of caverns would have 



belonged to the Tubeweavers. Many species of this tribe live 



Tube- j n cornerS; crannies, dark rooms, under stones, rocks, fallen trees, 



and like locations ' from which n 'g ht is lar S el y excluded. Others 

 secure their prey during night hours, although in this respect 

 they are not peculiar from other tribes. The transfer from 

 such a habit to a life within a cavern to which no light ever penetrates, 



