224 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



The block was laid upon a rough plastered cellar window (in my church cel- 

 lar) much frequented by spiders, and was overspun as indicated in the figure. 

 The ridge of the pyramidal structure drooped between the tips of the wire 

 hoop, quite like the main cable of a wire suspension bridge. 

 From this numerous diverging lines stretched on either side to 

 edge of the block and the window ledge beyond. Below 

 the ridge cable and within the side guy lines a maze of 

 thickened netted lines was spread, from w r hich support- 

 ing trestle like lines dropped down perpendicularly 

 to the surface of the block. The spider her- 

 self, with several white globular flossy co- 

 coons and a bevy of younglings be- 

 sides, was domiciled 

 within a series of lines 

 that extended from one 

 of the wire tips (left 

 hand of the cut) to the 

 stone window frame. The 

 resemblance of this struct- 

 ure to the wire bridges or 

 wooden trestlework of hu- 

 man engineers is apparent 

 at a glance. 



At times, 

 when the sit- 

 uation will al- 

 low, the spin- 

 ningwork of 

 Theridium 



FIG. 212. Theridium's silk suspension bridge. 



assumes even 



more decidedly the form of a nest. For example, in the horse stables 

 of " Almora," the country seat of a gentleman resident at Wallingford, 

 the windows are protected by a wide meshed wire frame. Within the 

 meshes and around the window frame a vast number of spiderlings of 

 Theridium tepidariorum had colonized. The scant lines which 

 Globular formed the original snares had gradually been thickened around 

 Struct- the mar gi nS) from which stay lines were thrown out in all di- 

 rections. In the course of time the snare assumed the globular 

 shape which is indicated in the cut. (Fig. 213.) Within the 

 centre, which was. more scantily woven and more open than 

 elsewhere, the spider was established. This condition of the central part 

 was quite the reverse of what one usually sees, viz., the thickening of the 

 web near the spider's habitat. The variation appears to have been caused 

 by the necessity of strengthening the points at which the guy lines and 





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