370 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



Cape Ann southward, burrowing in her characteristic perpendicular holes, 

 has in such sites a color quite corresponding with that of the white sand 

 in which she dwells.^ The same species taken further in the interior is 

 found of a darker hue, thus resembling the soil in which it lives. This 

 would appear to be a decided example of the adaptation of color to envi- 

 ronment, or, as better stated, the influence of environment upon color. 



Cambridge refers to like facts as marking English species. A Lateri- 

 grade, Xysticus sabulosus Hahn, so exactly resembles both in form and 

 color the little bits of gret, yellowish black, and red brown mottled stone, 

 found on the bare patches where turf has been pared off the heaths, that 

 until the spider moves it is almost impossible to detect it. Lycosa herbi- 

 grada, a gray spider marked with black and brown markings, is another 

 instance of exact adaptation to the gray, sandy heatlis where it occurs ; 

 while Philodromus fallax is equally well concealed by the perfect adapta- 

 tion to the coloring of the dull yellowish, sandy spots where alone it is met 

 with. The common and beautiful English Ejseira cucurbitina, found on 

 rose and other bushes, in gardens and woods, is of a clear, bright green 

 color with a brightish red spot at the hinder extremity of the abdomen ; 

 this spider, when, as it often does, it sits tucked up between the green 

 shoot and the axil of the leaf, looks exactly like a young bud just ready 

 to burst. ^ 



Mimicry and the survival of the fittest have been suggested to account 

 for this interesting habit. It is argued that those spiders, among the nu- 

 merous broodlings hatched out from the eggs, whose colors most 

 _^, ^^^ closely resemble those of the flowers alluded to above, are the 

 ones which survive, by reason both of the degree of protection 

 against enemies derived from their likeness to colors of the flower, and 

 their facility to capture prey because of the same resemblance, which would 

 naturally conceal their presence. In other words, those spiderlings which 

 by any chance happen to find lodging upon yellow flowers, or flowers most 

 closely colored like themselves, are the ones which survive the perils of 

 spider babyhood and grow to adult age. 



Before one fully accepts this theory it will be well to consider certain 

 difficulties. The most perilous age of spiders, as is well known, is that 

 which immediately follows exode from the cocoon. In a multi- 

 ■^ ^^ ' tude of cases in which these little ones entered life far removed 

 from any flowers corresponding with their normal color, how 

 are we to account for their preservation ? Certainly tliey did live and 

 retain their natural colors in spite of the absence of golden rods, black- 

 eyed Susans, ox-eyed daisies, and flowers of like hue. Moreover, one is 

 compelled to establish the fact that the opening up of these flowers cor- 



' See my notes on "The Turret Spider on C'otiin's Beach," Proceed. Acad. Nat. Sci., 

 Pliila., 188S, \tiiiie 33:-!. ^ Spiders of Dorset. 



