328 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



If we turn to the Tubeweavers we find a varied and interesting field 

 of spinning industry in the making of snares, nests, and cocoons. In all 

 of these it may be confidently said that the methods, as far as known, 

 are sulistantially the same as those described as prevail- 

 ing in other tribes. A few ilhistrations show this fact. 

 The interesting and well known water spider 



^iiwk^Wr'-^^'- 





Methods q£ Europe, Argvroneta aquatica, weaves in 



of Tube- 



weavers. 



Water 

 Spider. 



water a bell shaped tent (Fig. 314), within 



which she dwells, deposits her egg sac, and 



rears her young. The following observation indicates 



Fig. 314. The'beii shaped that evcu in this sccmingly unnatural element the 



uiTwate/spfdOT'^u^nder sauic general method characterizes the spider's weav- 



water. jng. Fig. 315 represents a patch of spinningwork 



made by this water spider upon a glass within which she was confined, 



and drawn by Mr. Underbill, i On examining the central part of this 



patch, it appeared, both to the naked eye and to the microscope, like 



a piece of the sjsider's cocoon. Certain broad threads at the edge of the 



patch at once explained the method by which this close and 



The even texture was obtained. They are represented by Fig. 315, c, 



as they appeared under the microscope. They seem to have been 



produced, as in the cases above described, by the spider erecting 



or placing, parallel to one another, a series of spinning tubes, which emitted 



separate and parallel threads, instead of lines directed towards one point. 



These bands Mr. Underbill supposed 



to be the product of the anterior 



spinnerets, while the other two 



threads, a and B, are emitted by the 



posterior and middle spinnerets. 



When Agalena noevia wishes to 



extend the borders of her sheet 



like snare, she proceeds 

 Agalena's • ,i 



Method. !" *^ ^^^^. ^'^^i ^^^^y' 

 ing first various lines be- 

 yond the margin to the desired dis- 

 tance, which lines are stretched 

 across the foliage or other surface 

 that forms the nest site. When 

 the desired mimber of the.se lines 

 has been laid down, the Tube- 

 weaver moves backward and for- 

 ward over them, spinning out all the while a stream of silk, at tlie same 

 time moving her long spinnerets up and down from the surface of the 



Fig. 315. Highly magnified piece of the Water spider's 

 web. a, a, B B, the .single original or warp lines ; c, c, c, 

 the banded filaments forming the weft. 



'Science Gossip," 1875, page 134. 



