MIMICRY OP SPIDERS. 51 



rapidly influence the organism of the creature that a change of color is 

 produced in liarmony with its environment. • I there raised this query : 

 Can a spider have the power to influence at will the chromatophores or 

 pigment bodies, so that she may change her color with the changing sites ? 

 Mr. H. H. J. Bell has recently communicated an observation^ which 

 appears to be confirmatory of this suggestion. While traveling along the 

 West Coast of Africa between two small towns on the Gold Coast 

 Mimicry, (^"g^^^t, 1892), he was attracted by the appearance of what he 

 supposed to be flowers upon the bushes bordering the path. On 

 examining these he found that they were the webs of an orbweaving spider, 

 whose spinningwork, according to the published description, resembles that 

 of Argiope, as heretofore fully described by me. The spider's body was a 

 light blue color; and the legs, which were symmetrically disposed in the 

 sliape of an X across a white ribboned hub, were yellow, ringed with brown. 

 The body of the spider resembled the corol of a flower, and the crossed 

 legs gave it the semblance of petals. Mr. Bell speaks of the illusion as 

 remarkable, and supposes this mimicry of an orchidlike flower serves not 

 merely to protect the spider, but rather as an attraction to butterflies and 

 other flower frequenting insects on which the arauead preys. 



The most interesting part of the observation, however, is the strange 

 facility which the spider possessed of changing its color. Mr. Bell captured 

 her in a white gauze collecting net, which was placed beneath 

 al°Col°"' ^^^^ ''^"'^ "^*'*^ which she dropped when disturbed, as is the custom 

 Changes. °^ "lanj species. As soon as she touched the net the blue body 

 color became white. On being shaken her body turned to a 

 dark greenish brown. She was then placed in a glass tube, and gradually 

 resumed her blue tint, but when shaken up always turned to a greenish 

 brown. When placed in spirits the spider's color became a gray brown, and 

 so remained. The observation was repeated with like result, except that 

 the second individual did not turn white, but passed immediately from 

 her normal blue into a dark greenish brown. I have no comments to make 

 upon this interesting and, as it seems to me, important observation, but 

 give it place here, as of undoubted value in its bearing upon the interest- 

 ing and perplexing problem of mimicry as it is presented in the life history 

 of the various aranead species. I have never observed and do not remem- 

 ber ever to have read of such instant and volitional changes of color. 

 The slight changes which I have noted in spiders having metallic colors 

 have been due to the play of light falling at and seen from different angles. 

 The numerous and striking changes in the Shamrock spider (Epeira trifo- 

 lium), so well illustrated in Plate I. of Vol. II., are produced gradually, 

 and cannot be compared with the chameleonlike changes of the blue Orb- 

 weaver observed by Mr. Bell. 



' Nature, April 13th, 1S93, page 558. 



