222 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



About the middle of May, the sumo spring, I watched the egress of a 

 whole colony of the young of Epeira insularis from a cocoon whicli I had 

 hung upon an ampelopsis vine outside my study window. They 

 r *r ency move d with great celerity and soon were widely scattered over 

 U ard the vine. All mounted upwards, not a single one descending be- 

 low the site of the cocoon; which habit, as I have observed, is 

 quite common to all species. A few days thereafter their tiny filaments 

 could be traced stretched from leaf to leaf over a large surface of the vine, 

 as high as ten and a half feet from the ground. But not a single web 

 was afterwards formed during the whole summer and autumn, and, as far 

 as I know, every individual perished. Those who are familiar with like 

 facts will readily perceive the necessity for the immense fecundity of fe- 

 male spiders in the production of eggs. Only under favorable circum- 

 stances can considerable numbers of any single colony reach maturity. My 

 observations on colonies of Epeira labyrinthea and Epeira triara- 

 Mortality nea snow fa a i twenty, thirty, or fifty may survive for a short 

 mong period, and construct in the same vicinity their little orbicular 

 ling's snares. But these, too, soon perish under the combined assaults 

 of their natural enemies and unfavorable weather. It is probable, 

 indeed I believe that it is quite certain, when cocoons are located in spe- 

 cially favored spots, and the young inhabitants issue forth under specially 

 favored circumstances, that the majority of them pass beyond the period 

 of babyhood and attain middle growth, and reach in goodly proportion 

 mature life; but these examples must be comparatively rare. 



VI. 



My observations of the habits of spiderlings immediately after egress 

 are confirmed by such brief notes as other observers have made in natural 

 site. Emerton says (speaking apparently from observation) that 

 a brood of young Epeiras may often be seen living in a common 

 web, and looking like a ball of wool in the top of a bush ; while 

 below them, connected by threads to their roost, are the skins left at their 

 second moult, and further down, also connected by threads, the cocoon. 1 

 I have often seen the young of Theridium tepidariorum, and of the long 

 legged cellar spider, Pholcus phalangioides, hanging in these cottony clus- 

 ters at the top of the maternal snare, the mother herself suspended beneath. 

 The Orbweavers thus appear to agree in this habit with these Lineweavers. 

 Wilder also has a brief reference in the same direction to the young of 

 Nephila plumipes, which, he says, even after leaving the cocoon, are more 

 or less gregarious, always keeping in companies, and preserving good order 

 while moving. 2 



1 Structure and Habite, page 110. 



2 Proceed. Amer. Acad. Arts and Sciences, VII., 1865, page 56. 



