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 ? 
TV. 
Closely associated with spiders making a horizontal snare is the Bas- 
ilica spider, the sole known representative of species that spin what I have 
called a Domed orb. The 
history of this species, 
which I have heretofore 
recorded, is as follows:! 
In the month of June, 
1877, I was en- 
camped upon 
ae the hills of the 
basilica. 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 
which the object of this 
sketch was discovered. 
Her snare was hung about 
two feet from the ground, 
upon a bush which stood 
in the midst of a grove 
Domed 
Fic. 154, The dome shaped snare of the Basilica spider. r, the reti- : 5 Pais 
telarian snare; d, the dome. of young live oaks. ‘This 
1 Proceedings Academy of Natural Sciences of Philadelphia, 1878, pages 124-132. 
2 Observations upon the former species are recorded in a volume entitled “The Agricul- 
tural Ant of Texas,” J. B. Lippincott Company, Philadelphia. For some account of the 
Cutting Ants see “Proceedings Acad. Nat. Sci. Phila.,” 1879, page 33, and Chapters XIII. and 
XIV. in my popular work entitled “The Tenants of an Old Farm.” 
