NESTING HABITS AND PROTECTIVE ARCHITECTURE. 



289 



Architec 

 tural Va- 

 riations. 



constant 

 species. 



II. 



As a rule, the various groups of Orbweavers differ from each other and 

 agree within tliemselves in characteristic nest forms. The form prevaihng 

 in each family is substantially the same; each species seems to 

 adhere quite steadily to one characteristic form ; but there are 

 some marked variations in the habit of certain species, as in 

 the Insular spider, whose nest architecture we have seen is not 

 in form among the individuals of that 

 Indeed, the variation extends without a 

 doubt to the habits of the same individual under 

 different circumstances. This opens a most inter- 

 esting feature in the story of spider industry, which 

 may as well be kept in mind as we proceed with 

 the description of these nesting habits. It will be fig. 262. Nest of strix within 



Q Toll f*n 1 f*s,i 



obvious that some of the variations are adaptations 



to changed environment. Some of the most decided of these variations have 



been observed in the nest architecture of Epeira strix. I observed two of 



this species domiciled in the beautiful hedgerows of a New England meadow, 



w^ithin nests of several rolled leaves, which had an inside lining quite like 



that which is made by Insularis. Both nests were below the orb, one ten 



inches below. The second examj^le had for her nest a very bright red 



rolled leaf with a tube inside of it, which made a strikingly pretty object. 



The ordinary nest of Strix when domiciled in the open field or wood 



is a rolled leaf. A single leaf is taken, the edge pulled up, drawn under, 



and fastened by adhesive threads into a rude cylinder, within 



Varia- ^vhich the spider hides during the daytime. (Fig. 262.) A 



. , , thread cormection with the foundation lines of the snare is 

 Adapta- 

 tions, sometimes maintained ; but rarely with the centre of the orb by 



a taut trapline, as is the habit of the Insular spider. For this 

 reason I have often been greatly puzzled, and not infrequently foiled, in 

 searching for Strix in the neighborhood of her orb, which one comes at 



last to recognize on sight with tolerable accuracy. 

 This severing or concealing of her trail threads is 

 undoubtedly a protection against raiding natural- 

 ists; but I cannot imagine any security which it 

 gives against natural enemies. This cylindrical nest 

 will often be spun within any convenient cavity, as, 

 for example, a bit of curled birch bark, Fig. 203, a 

 specimen found on an island in St, Lawrence River, 

 A second form of the nest of Strix varies from tlie rolled leaf nest in 

 having the edges of the two adjacent leaves bent towards each other and 

 lashed together on the exterior at the juncture by silken cords, and on the 

 interior by adhesive tissue web. An oval opening is left at the united 



Fig. 263. Nest of Strix within 

 curled birch bark. 



