NEST MAKING : ITS ORIGIN AND USE. 



325 



spreading out the carpet like structure or the pouched bag which form 

 respectively the snares of those species. 



I have described at length the method in a paper upon the habits of 

 the Purseweb spider, 1 and it will fairly represent the action of all other 

 species making similar dwelling places. The characteristic tube 

 , of the Purseweb spider is spun against the trunk of a tree, ex- 

 tending several inches above the surface of the ground and 

 about an equal distance beneath it. (Fig. 303.) The first stage in con- 

 structing this tube is to stretch a series of lines about two inches from the 

 surface of the ground to various points on the surface of the tree, until a 

 circular or nearly circular row is formed, extending from the tree to the 



FIG. 308. 



FIG. 309. 



FIG. 310. 



FIG. 308. The frame of original lines stretched against a stock. FIG. 309. The frame partly covered over ; 

 the spider is seen within putting on the weft. FIG. 310. The completed tube, with a small cross tube 

 woven at the base. 



ground. This forms a frame of straight lines, which is the foundation 

 of the tube. (Fig. 308.) The spider now passes within this structure, and, 

 clinging to the threads with her feet, moves her abdomen simultaneously 

 backward and forward and up and down, meanwhile issuing from the 

 spinnerets thickened lines, which adhere to the framework. In other 

 words, the framework constitutes the warp, and the lines issued there- 

 after the woof of her texture. (Fig. 309.) As the threads are drawn out 

 from the spinnerets they are beaten down upon the frame lines by the 



1 Proceedings Academy Natural Sciences, Philadelphia, 1888, pages 203-18. " The Nest- 

 ing Habits of the American Purseweb Spider." 



