334 



AMERICAN SPIDERS AXD THEIR SPINNINGWORK. 



all the characteristics of our northern species, but are decidedly larger. 

 No marked influence appears to have been exerted upon the coloration of 

 the spider itself. But other collections indicate contrary conditions. 



The species was collected pretty freely by the naturalists of the U. S. S. 

 "Albatross," in its explorations along the shores of the southern Atlantic 

 and the Pacific, showing an immense distribution over the en- 

 Epeira ^ire Western Hemisphere. Dr. Marx remarks that specimens col- 

 rinthea l ecte d at the Straits of Magellan are hardly recognizable, for its 

 color has greatly changed. The dorsal folium is nearly obliter- 

 ated. Only two lighter spots at each side remain, and the whole body is 

 covered with a long, dense pubescence. 1 



If Dr. Marx is correct in his surmise that Epeira cooksonii Butler, 

 which lives in great abundance on the Gallapagos Islands, is related to our 

 Epeira domiciliorum, and that the latter spider has undergone on the Pa- 

 cific coast so great a change in form and coloration as to be identical 

 with my Epeira vertebrata, this species will afford another example of the 

 influence of climate upon color. 2 I am not satisfied, however, that the 

 last two named species are identical. On the other hand, certain species, 

 as notably Argiope cophinaria and argyraspis, have undergone a transcon- 

 tinental distribution, covering wide extremes of climate and conditions, 

 without experiencing any notable change in general appearance. 



These examples will be sufficient as illustrations of the fact that the 

 influence of climate must vary according to species. The fact is that some 

 of the species probably arc more elastic and impressionable in their nat- 

 ural constitution, and thus are more sensitive to radical changes in envi- 

 ronment, while others are able to resist such changes more vigorously, and 

 thus retain their characteristics through extreme changes. 



Spiders that live upon plants, as a rule have colors that arc har- 

 monious with the prevailing greens and yellows, and admixtures thereof, 

 of branches, leaves, and flowers. Spiders that nest in stables, 

 In fluence houses, on fences, and like locations, ordinarily have dusky 

 ronment colors > harmonious with the environment; as, for example, The- 

 ridiuin tepidariorum, Agalena nasvia, Tegenaria medicinalis. 

 However, I do not find that any great difference in color is observable 

 in the above species when they nest in foliage, as is often the case, at 

 least with Agalena and Theridium. It might be said, perhaps, that there 

 is a slight tendency to darker hues and a more uniform color when the 

 spiders are found in the first named locations. 



Ground spiders, as the Lycosids, generally have colors of neutral grays 

 that blend well either with the soil, with rocks, or with stalks of grass 

 and weeds, especially when the latter are somewhat dry. Lycosids found 

 in the neighborhood of streams do not seem to be especially influenced by 



1 Proc. U. S. National Mus., Smithsonian In.stitn.. Vnl. XII., page 209. 2 Id., page 210. 



