MATERNAL INSTINCTS : MOTHERHOOD. 179 



taken them on the highest railing of the dome of St. Peter's in Rome ; 

 have seen their round webs swinging against the cliffs of Mosquito Mount- 

 ain Pass in Colorado, more than ten thousand feet high ; have found them 

 upon the mountains of Scotland ; and captured the British Epeira umbra- 

 tica from snares spun against tlie basaltic columns of Fingal's Cave. 



Their fixed positions are, of course, determined by their ability to 

 obtain food therefrom ; and, as their food is insects, the limit of insect 



life must also be the limit of spider life. For, although spiders 

 J . . are frequently at the mercy of the winds and are carried great 



distances when they are young, during the aeronautic stage, they 

 cannot long sustain themselves and propagate their species if they chance 

 to fall upon 230sitions where it is difficult or impossible to obtain generous 

 supplies of insect food. 



In seeking a spot upon which to place their cocoons, most Orbweavers 

 go a little distance from their snares and construct the cocoon against the 



outer surface of a bush or tree, rock or wall, or cover it up 

 g . . within a leaf. As a rule, the disposition to find a secluded spot 



is quite manifest, but there are many exceptions. Other species 

 deposit their cocoons within their webs, stringing them along one of the 

 radii of the orb, as in the case of Uloborus, Epeira caudata, and Epeira 

 bifurca ; or suspend them within a maze of crossed lines which overhangs 

 the orb, as in the case of the Labyrinth spider. Others, again, as with 

 Argiope, will frequently swing their cocoons within a specially prepared 

 mass of crossed and netted lines, which are hung to branches or boughs, 

 leaves, or blades of grass. 



What is said of Orbweavers as to cocooning site is substantially true 

 of the other Tribes, with, of course, such variations as are required by 

 essential differences of habit and structure. For examj^le, those Seden- 

 tary spiders, as the Lineweavers, which suspend their snares in positions 

 quite like those of Orbweavers, also follow closely that Tribe in the gen- 

 eral principle of selection for cocoon sites. In other words, they hang 

 their cocoons in some part of their snare, or somewhere near, hidden be- 

 neath a convenient cover, or in a neigli])oring retreat. 



So also many Tubeweavers, and the Tunnelweavers even more persist- 

 ently, attach their cocoons to some part of their web, or weave one of their 

 characteristic tubes around the egg case when it is once spun. In these 

 cases the cocoon site is pretty sure to be identical with the dwelling place 

 and snare. 



Among Wanderers the home site has less influence upon the cocoon 

 site. As these animals pursue their prey over a more or less extended 



range of territory, the site of the cocoon is dependent on the 



place where the hour of maternity may overtake the females. 



Wherever they happen to be, the Saltigrades and Laterigrades 

 will spin a tubular tent, enclose within it their cocoon, and there remain 



