352 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



Therid- 

 ium ner- 

 vosum. 



of the spider forming the snare, resulting from some morbid physiological 

 condition? Could it be that an Orbweaver had straggled upon the web of 

 this Lineweaving species, and left some traces of her presence by emitting 

 her peculiar viscid beads which, forming upon the retitelarian meshes, left 

 the traces of the stranger's presence ? Could I have been mistaken ? 



I should not have ventured even to mention this experience had I not 

 noticed the statement made by Mr. Edward H. Robertson, 1 that the snare 

 of Theridium nervosum in England is characterized by a similar armature. 

 He states positively that house flies when trapped upon the snares of 

 this species are held very tenaciously by the viscid globules which are dis- 

 persed over the intersecting lines. I do 

 not remember to have noticed this feature 

 attributed to any Lineweaving 

 species by any other observer. 

 That it must be a rare phenom- 

 enon is manifest from this fact; 

 but may it not be that a more careful 

 examination, with this point distinctly in 

 view, will show results of a more decided 

 character ? 



At all events, it is proper to say that 

 there remains the possibility that one of 

 the most striking industrial characteristics 

 of the Orbweaving spiders may have been 

 bestowed in some degree upon the tribe of 

 Lineweavers whose species are most closely 

 related to the Orbitelarise, both in struct- 

 ure and economy. Thus in this partic- 

 ular, also, we are able to trace, though it 

 must be confessed in a not very decided manner, an analogy between 

 Orbweavers and at least two of the other tribes of Aranea3, viz., Tube- 

 weavers and Lineweavers. 



III. 



In the preceding section I have shown how one may rise to the complex 



orbweb from the simplest form of snare a few lines. It will perhaps 



equally illustrate the general harmony of habit which I have 



Another frequently pointed out, and the danger of fixing any arbitrary 



point from which development has progressed, if I show that one 



may reach the same terminus from a very different starting point, 



viz., the tubular snare. Indeed, my first conclusions settled upon this as 



the most natural point of departure, since (as I have heretofore shown) the 



FIG. 345. The mesh formed snare 

 of Theridium differens, showing 

 viscid beads. 



1 "Science Gossip," January, 1868, page 12. 



