MIMICRY IX SPIDERS. 369 



It would be strange if all these were one species, differently colored accord- 

 ing to the place they dwell in, and having power to change from purple 

 or white to yellow at will ; yet this seemed probable to us. Or was it 

 that a species had developed these different varieties, each adapted to live 

 on a certain plant? However this may be, the arrangement evidently 

 resulted in a twofold advantage, in that it enabled the spiders to escape 

 the peering eyes of birds, and at the same time to lie in wait unperceived 

 for the insects of various sorts that frequent such flowers in great num- 

 bers. In no case, it may be added, did we see a purple spider on a yellow 

 flower, or vice versa." 



Mr. Cambridge has observed and recorded like facts of Misumena vatia 

 in England.' He says: "I find this spider very commonly in the blooms 

 of the great mullein, Verbascum thapsus, to which the pale yel- 

 E a-lish ^o^'isl^ hues of the spider are well suited for its concealment in 

 Species. ^^^® yellow blossoms. An allied spider, Thomisus onustus, found 

 on the heather blooms, and upon some other pink flowers, is 

 beautifully tinted with pink, chiefly in its younger and feebler stages. 

 The Rev. C. W. Penny (of Wellington College, Wokingham) tells me that 

 he has found examples of this spider on yellowish blossoms, and that 

 these examples are generally of a yellowish hue, quite devoid of the pink 

 color of those found on pink blooms. I am inclined to think that this 

 is not invariable, inasmuch as I have found here the more mature exam- 

 ples, which are generally devoid of pink coloring, also on the pink heather 

 blooms. The protective resemblance of color would not be so necessarj'-, 

 in the above instance, for the protection of the more mature as for that 

 of the younger spiders, and therefore we might expect to find the former 

 on flowers of any color growing where the spiders are found; while I have 

 certainly only met with the younger pink colored spiders on the pink 

 heather blossoms." It is important to note the above exception as to 

 adult forms. 



Most other Laterigrade spiders known to me are of a dull gray or 

 brownish color. As they are frec^uently found resting upon the bark of 

 trees, over which they prowl seeking their natural prey, their resemblance 

 to the color of the bark is quite striking, and might serve to protect them 

 alike from the observation of enemies and of victims (Plate III., Fig. 3.) 



Among the Citigrade or ground spiders, the same fact may be noted. 



Their colors are generally neutral or dull grayish, mottled or 



Mimick- striped with black. They thus blend easily with the colors of 

 ing" Bark ./ ./ 



, the ground and stalks of plants and grasses among which they 



Ground, fi'cquently move. Some of these spiders when found in littoral 

 sites take upon them the color of their surroundings. For ex- 

 ample, the Turret spider, which I have observed along the seashore from 



Spiders of Dorset. 



