164 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



fauna, while Gasteracantha has never been found farther north than the 

 southern areas of our Gulf States. Both these genera, like Nephila, appear 

 to be more especially characteristic of the tropical spider fauna, among 

 which they also have a great variety of prolific and peculiar species. 



One's curiosity is sorely puzzled to know why our three northern repre- 

 sentatives of Acrosoma have been able to find and hold a place among 

 the fauna, not only of the temperate, but of the more northern areas, 

 while other species, and the genus Gasteracantha in all species, have ceased 

 their northward march at the line already indicated. Or has the progress 

 been in the reverse direction — from the north towards the south? And 

 are our indigenous species of Acrosoma the survivors of a fauna that once 

 held sway throughout the region stretching from New England to the 

 Pacific? 



IV. 



Closely associated with spiders making a 

 ilica spider, the sole known representative of 



Domed 

 Orbs, 

 Epeira 

 basilica. 



Vui. 154. The dome shaped snare of the Basilica spider, r, tlie reti- 

 telarian snare ; d, the dome. 



horizontal snare is the Bas- 

 species that spin what I have 

 called a Domed orb. The 

 history of this species, 

 which I have heretofore 

 recorded, is as follows :i 

 In the month of June, 

 1877, I was en- 

 camped upon 

 the hills of the 

 Colorado River 

 of Texas, a few 

 miles southwest of Aus- 

 tin, studying the habits 

 of the agricultural and 

 cutting ants. 2 A limited 

 portion of my time was 

 given to observing spi- 

 ders, in the course of 

 wliicli the object of this 

 sketch was discovered. 

 Her snare was hung about 

 two feet from the ground, 

 upon a bush which stood 

 in th(^ midst of a grove 

 of young live oaks. This 



1 Proceedings Academy of Natural Sciences of Philadelphia, 1878, pages 124-132. 



■'^Observations upon the former species are recorded in a vohnne entitled "Tlie Agricul- 

 tural Ant of Texas," J. B. Li])j)incott Com])any, Pliiladclpliia. For some accoiuit of tlie 

 Cutting Ants see "Proceedings Acad. Nat. Sci. IMiila.," 1S7!», page o3, and Chapters XIII. and 

 XI\'. ill my popular work entitk'd "The Tenants of an Old Farm." 



