NESTING HABITS AND PROTECTIVE ARCHITECTURE. 289 



II. 



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



agree within themselves in characteristic nest forms. The form prevailing 



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



Architec- ac j nere quite steadily to one characteristic form; but there are 



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

 nations. ' 



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

 constant in form among the individuals of that 

 species. 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 

 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, 

 within 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 example 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- which the spider hides during the daytime. (Fig. 262.) A 

 Ada ta thread connection with the foundation lines of the snare is 

 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, 

 FIG. 263. xest of strix within for example, a bit of curled birch bark, Fig. 263, a 



specimen found on an island in St. Lawrence River. 



A second form of the nest of Strix varies from the 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 



