230 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



IX. 



Naturalists have at various times recorded descriptions of " gregarious 

 spiders," which have attracted especial interest by their singularity. Dar- 

 win mentions a " gregarious Epeira " found in great numbers 

 Grega- near g^ p e Bajada, th e capital of one of the provinces of La 



7*1011 ^ 



. , Plata. The spiders were large, of a black color, with ruby marks 



Darwin. on their backs, and were all of one size, so that they " could not 



have been a few old individuals with their families." l The ver- 

 tical webs were separated from each other by a space of about two feet, 

 but were all attached to certain common lines of great length, that extend- 

 ed to all parts of the community. In this manner the tops of some large 

 bushes were encompassed by the united nets. These gregarious habits in 

 so typical a genus as Epeira seemed to the distinguished author to " pre- 

 sent a singular case among insects which are so bloodthirsty and solitary 

 that even the sexes attack each other." In point of fact Mr. Darwin 

 had only come across a brood of Epeiroids, who, for some reason of en- 

 vironment, as protection from the wind, freedom from enemies, or abun- 

 dance of food, or from sluggishness of nature, had kept within a com- 

 paratively limited space after egress from the cocoon. It is therefore 

 not allowable to speak of this colony as a " community," in the ordinary 

 sense of the word as applied to such social insects as ants, termites, bees, 

 and wasps. 



Don Felix de Azara had the same misconception, if indeed it be one. 

 Although the family of spiders, he says, is for the most part regarded as 



of solitary habit, there is one in Paraguay which lives in a com- 



Spider munity to the number of more than a hundred individuals. 



omir Each spider builds a nest larger than a hat, and suspends it aloft 



Azara a ^ the can( >py of a high tree or the ridge piece of a roof, in such 



a manner as to be a little sheltered from above. From this a 

 great number of threads issue in all directions, into every available part. 

 The lines, in fact, are fifty or sixty feet long, white and thick. - They are 

 traversed by other threads of great fineness, upon which are entangled 

 winged ants and other insects, which serve as food for the community of 

 spiders, each individual of which eats what itself had trapped. These spi- 

 ders all die in autumn, but leave in their nest eggs which are hatched out 

 the ensuing spring. 2 In both the above cases the facts are undoubtedly 

 recorded correctly; but the inference from them can scarcely be justified. 



Darwin, who briefly refers to the account of Azara, appears to be quite 

 right in thinking the Spaniard's " community " to be of the same species 

 as his own, although Walckenaer gives in a note the opinion that the 



1 Voyage of Beagle, Vol. III., Zoology. 



2 Voyages dans L'Ame'rique Meridionale. Par Don Felix de Azara. Tome Premier, page 

 212, 1806. Walckenaer's French edition. 



