286 AMERICAN. SPIDERS AND THEIR SPINNINGWORK. 



upon the inside, sealed, covered, and swathed within the characteristic co- 

 coon, and all done as accurately as though the creature had wrought under 

 the most satisfactory conditions. Readers who have followed the methods 

 of cocoon weaving as detailed in the preceding chapters will be able to 

 appreciate the acuteness and accuracy of that sense of touch, and what- 

 ever other faculty may be associated therewith, by which such an in- 

 dustry was wrought, and share the wonder that it could have been 

 done in total darkness. Like facts are true of other tribes than Orbweav- 

 ers, particularly Tubeweavers and Salti grades, with which I have experi- 

 mented. 



The fact that spiders are able to spin their cocoons not only in the 

 dark, but without apparent organs of vision, is demonstrated by the case 

 of the well known cave spider, Anthrobia mammouthia. Professor Pack- 

 ard found this species in Mammoth Cave, and was fortunate enough to 

 collect a cocoon belonging to it. This, of course, shows that the delicate 

 work required in constructing this object can be wrought by touch alone. 

 So also the cavern Linyphians, although having eyes, dwell in total dark- 

 ness and weave snares and cocoons. 



I have often found the peculiar tubular nest of the Saltigrades spun 

 within boxes in which they had been captured. These spiders have, per- 

 haps, the most perfect organs of vision of any of the order. Yet 

 big. ing they are able to do quite as good weaving in the dark as in the 

 light. No one who has watched them stalking prey during the 

 day could well fail to conclude that they are guided by a tolerably accu- 

 rate sense of sight. Their rapid and marked change of manner when 

 prey is "sighted," the mode of approach, like the action of a cat creep- 

 ing upon a bird, the peculiar behavior displayed when the final spring 

 is made, are not to be accounted for on any theory other than a keen 

 sense of sight. So also with Citigrades. I have seen young Dolomedes 

 sexpunctatus leap from the side of a box and catch a fly " on the wing," 

 and return to its perch by the rebound of its dragline. Such an act not 

 only shows ability to see, but also some faculty to estimate distance, unless 

 we suppose it to have been a chance shot. 



In Laterigrades similar action may be observed. Like Saltigrades, they 

 are arboreal in their habits, and crouch for prey and steal upon it. One 

 of our largest indigenous Laterigrades, the Huntsman spider (Heterapoda 

 venatoria), received from Florida and kept" in captivity, permitted a large 

 fly placed in her cell to run between the legs, fly into the face, alight on 

 the back, without any attempt to capture it. In the course of time, how- 

 ever, the fly lit on the side of the box a short distance in advance of the 

 Huntsman. She perceived it, crouched, slowly moved her limbs, stealthily 

 and by almost imperceptible advances approached, then swiftly shot forth 

 her claws and secured her victim. The behavior was quite similar to that 

 shown under kindred conditions by animals with w r ell organized sight. 



