[120] 



Spibcre : ^beir Structure anb Ibabite. 



By William Horner. 



Second Paper. Plate 12. 



THE webs of the Retiary Spiders have each a distinct 

 character, so much so that you can tell by inspection to 

 what family a given web may belong, and, indeed, in many 

 cases they betray even specific differences. However, not to 

 enter too much into detail, it will suffice to remark that some 

 exhibit an irregular network of lines in all direcUons, and in 

 different planes ; others resemble a horizontal sheet of fine 

 webbing, supported by its margin, and secured by fine lines 

 running from various parts of its surface, both above and below. 

 Others, including those of the domestic spider, are large and 

 close-textured ; and when in the corners of buildings, contain a 

 tubular hiding-place for the proprietor, placed in the angle 

 formed by the walls. 



There are some webs, however, which deserve a more detailed 

 description, especially those of the Epeiridce^ sometimes called the 

 Geometric Spiders, from the symmetry and regularity of plan 

 which characterizes their work. They usually suspend their nets 

 in an oblique or vertical position on shrubs or buildings ; and 

 their first operation is to enclose an area, no matter of what 

 figure, with threads of sufficient strength. This is done by 

 walking round the space destined for the snare, and laying down 

 threads from point to point, until it is enclosed by straight lines 

 forming an irregular polygon. Should the spider meet with 

 inaccessible openings in the course of her walk, she has more 

 resources than one. She may drop a perpendicular from one 

 spot to another, or she may swing herself across by the aid of a 

 breeze, and so reach a convenient spot. Should this be imprac- 

 ticable, she proceeds as follows : — She has no power to eject a 

 thread from her body in whatever direction she pleases, but she 

 avails herself of currents of air, and on their wings sends out her 

 lines to astonishing distances. But inasmuch as her threads, when 

 entire, are too heavy to yield to a moderate breeze, while the 

 separate strands which compose them are moved by the slightest 

 breath, she uses her spinning-tubes separately : emitting their 

 liquid gum, and turning her face to the wind, she allows it to be 



