SPIDERS AND INSECTS OTHER THAN ANTS 385 



placed in a tightly fitting box, the inside of which was painted 

 a certain color. (This box was called a color box). A piece of 

 card-board the same color as the inside of the color box was 

 arranged above the aquarium in such a manner as to reflect 

 that color into the aquarium. The colors used were black, white, 

 yellow, green, blue. He then cut a number of one by fifteen 

 millimeter paper slips that were so colored as to match the 

 inside of the color boxes. Four slips of each color were placed 

 in each jar. In selecting slips to build into their cases, the 

 larvae did not display any color preference. At the beginning 

 of his experiments on the spiders, Pearse tested the spiders' 

 reactions towards a beam of white light and demonstrated that 

 the spiders do not exhibit any form of phototropism. Other 

 preliminary experiments demonstrated that although these 

 spiders occasionally change in color until they resemble the 

 environment, yet the change takes place too slowly to be of 

 any protective value. The real tests were of two kinds: experi- 

 ments with color-boxes and experiments with flowers. In 

 nature some specimens of the species examined are white and 

 others are yellow. One vertical half of each color box was 

 painted white and the other half yellow. By means of a small 

 opening, the spiders were passed, through a narrow tube, into 

 the box at the place where the two colors met, and a record kept 

 of the side into which the spider went. In the flower experi- 

 ments, a spider was suspended, by means of a fine thread, half 

 way between a yellow and a white blossom, and a record made 

 of which way the spider attempted to go. Neither type of 

 experiment gave any evidence that the spiders exhibited color 

 preference. Pearse experimented with Crustacea as well as 

 insects and, as a result of all his experiments, he concludes: 

 " It cannot at present be affirmed that any protectively colored 

 arthropod reacts towards colored objects or backgrounds in 

 such a way that it can be said to have even an instinctive knowl- 

 edge that it is protectively colored; i.e., arthropods do not 

 choose the most favorable color environment on account of 

 color." The experiments warrant the conclusion; but it must 

 be remembered that proving that certain insects do not exhibit 

 color preference does not disprove that insects possess color 

 discrimination. 



