62 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



Founda- 

 tions 

 by Air 



Orbweavers who move at once from the beginning of a foundation to its 

 completion as though directed by a sure knowledge ; one cannot say by a 

 sure experience, for in point of fact this behavior is not the result of ex- 

 perience, inasmuch as it is observed in the youngest animals, and on the 

 other hand adults are quite apt to show the confused and indeterminate 

 action above referred to. 



The second mode of securing an orb foundation is by means of air 

 currents. It has been questioned by naturalists whether the Orbweaver 

 ever pursues any other method than that of carrying around the 

 foundation lines. As recently as A. D. 1881, so good an arach- 

 nologist as Mr. Cambridge expressed the belief that this is the 

 Currents. usua ^ mode of proceeding, and that air currents are never 

 utilized for the construction of orb foundations. 1 This opinion, 

 however, he shortly afterward abandoned, yielding to the facts presented 



by other arachnologists. 2 

 I have elsewhere treated 

 the question, at some 

 length, 3 and now present 

 the evidence that the 

 prime foundation lines 

 of orbwebs are often laid 

 by means of air currents. 

 In a great number of 

 cases I have observed 

 the Orbweavers 

 passing from 

 point to point 

 by means of lines emitted 

 from their spinnerets and 

 entangled upon adjacent 

 foliage or other objects. 

 Any one who will note with ordinary carefulness the movements of orb- 

 makers among shrubbery towards the close of a fair evening, may see such 

 examples. These mimic "suspension bridges" are of various lengths, owing 

 to the direction of the wind and the position of the spider relative to the 

 standing objects around it. Lines of two, three, and four feet are frequent ; 

 lines from seven to eight feet occur often ; I have measured one twenty-six 

 feet long, and in several cases have seen lines strung entirely across country 

 roads thirty or forty feet wide. 4 Many of these lines I have seen carried by 



Bridge 

 Lines. 



FIG. 60. Orbwebs on water plants in a pond. 



1 Spiders of Dorset, Rev. O. Pickard-Cambridge, Vol. I., Introduction, page 21. 



2 Op. cit., Vol. II. 



3 Proceedings Academy Natural Sciences of Philadelphia, 1881, page 430, seq. "How 

 Orbweaving Spiders make the Framework or Foundation of Webs." 



4 Lister, the father of English araneology, observed such lines stretched between trees and 

 over streams. Tractatus Araneis, page 8. 



