326 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



spinnerets, not interwoven with them. AVhen a sufficient number has been 

 laid upon the original frame, by the repeated spinning and beating action 

 of the spider, the whole presents the appearance of a thickened sheet 

 wrought into the form of a tube. (Fig. 310.) 



I have observed the overspinning of an- under- 

 ground burrow by a Purseweb in a glass jar. The 

 same method was followed, except that the frame lines 

 were .spun against the concavity of the 

 burrow and the inner surface of the glass. 

 The spider then proceeded to thicken 

 over the frame by spinning against it lit- 

 tle ribbons of silk and beating them down 

 with her long spinnerets. When hang- 

 ing head downward, with claws clasping 

 the frame lines, and spinning upward 

 against the roof of her burrow (Fig. 312), 

 she presented to the observer a rather 

 odd appearance. No doubt this is the 

 mode by which the spider silklines the 

 underground part of her tubular snare 



Fig. 311. Purseweb spider's nest. View below which Cxtcuds beneath tllC Saud SOmC- 



ground, as well as above. The subterranean ^imeS aS far aS aboVC the SUrfaCC, and is 

 terminus is expanded and branched. 



either single, or branched, after the man- 

 ner represented in Fig. 311. (See also Fig. 303.) 



The same method of spinning is used by our American tarantula, Eu- 



rypelma hentzii, in weaving the rug upon which it often loves to stay 



when in artificial confinement. In the act of spinning, the 



The Ta- {qt^^ posterior spinnerets are curved upward and forward (which 



Rug-. 





out 



is, indeed, an habitual position with this tribe), and from the 

 spinning tubes along the exterior part of the spinneret are given 

 numerous fine threads. 



These are pressed to the ground 

 by the downward motion of 

 the spinnerets. The abdomen 

 is then lifted up, and by tliis 

 action the threads are drawn 

 out. Again the downward mo- 

 tion is repeated, and simulta- 

 neously the end of the abdo- 

 men to which the spinnerets 

 are attached receives a lateral 

 motion that causes the threads to be spread over the surface of the 

 ground. At the same time the animal slowly moves its whole body 

 around, as ui)on a pivot, thus dispersing the silk over a circular patch of 



Fig. 312. Purseweb spider working the weft on an 

 underground fVame. 



