156 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



Vol. I., page 223), it is a constant tendency of Line weavers to thicken the 

 upper part of their snares until they sometimes have a quite sheet like 

 appearance. 



Nothing could be more interesting than a study of the life of these 

 creatures thus doomed to perpetual darkness in the bowels of the earth. 



To a great extent their natural history must be a matter of 

 Their 

 p , speculation. That they make snares we know, and the character 



of those snares is without exception the most rudimentary spun 

 by spiders, namely, a series of intersecting lines drawn from point to 

 point. The fact that they make snares implies that there must be some 

 creatures to be ensnared upon which they feed, and these creatures must, 

 of course, be less in physical power than themselves. What insects form 

 the basis of their food ? Among the insects occupying similar American 

 caverns are minute delicate mites, and Professor Packard conjectures that 

 these, together with young Podurse, may form a portion of their food. 



Moreover, these cave araneads have sufficient vitality to propagate their 

 own species. The old story of wooing and mating goes on in these regions 

 of unbroken darkness just as it does in the sunlight and among the flow- 

 ers and shrubs above. Mother love is not quenched by the endless gloom, 

 and the tiny creature of the cavern spins and cares for its tiny cocoon 

 just as does its more favored sister of the sunlight. The number of eggs 

 within the cocoons is very small in some species, according to the state- 

 ments of Professor Packard from two to five in Anthrobia, but in others 

 the excess of life is quite sufficient (there being thirty or forty in the co- 

 coons of Nesticus pallidus) to justify the inference that the chief supply 

 of food for these cave spiders is drawn from their own numbers. In other 

 words, they feed upon each other, and these Plutonic children of Arachne 

 must continue their generations largely by cannibalism. 



The influence of this mode of existence upon the structure and senses 

 of these cave spiders will be considered elsewhere. It may be fitting, how- 

 ever, to add here an experience which throws some light upon the manner 

 in which the animals might have been originally conveyed to 'these sub- 

 terranean abodes. One summer while examining the limestone 

 Origin caverns in central Pennsylvania, located among the Allegheny 

 -p a Mountains, in what is known as the Scotch Valley, not far from 

 the city of Altoona, I stood in the channel of a small stream in 

 the neighborhood of Sinking Spring. Looking forward, towards the source 

 of the stream, I saw the waters flowing down towards me, but gradually 

 diminishing, with no apparent reason, until, near the spot where I stood, 

 the stream dwindled to a mere thread and disappeared. It produced a 

 curious sensation to stand thus in midchannel and see a flowing brooklet 

 lost to one's sight before it reached the point where, under ordinary cir- 

 cumstances, it would have swept around the feet of the observer. The 

 secret, however, was readily explained, for the whole section underneath 



