COLOR IN ANIMALS 129 



border of the dried-tip more fluid part, which, as the leaf is 

 rarely horizontal, often runs for a little way toward the 

 margin. The spider, which belongs to a family, the Tho- 

 misidtz, possessing rather tuberculated, thick, and prominent 

 abdomened bodies, is of a general white color ; the underside, 

 which is the one exposed, is pure chalk-white, while the lower 

 portions of its first and second pairs of legs and a spot on 

 the head and on the abdomen are jet black. 



" This species does not weave a web of the ordinary kind, 

 but constructs on the surface of some prominent dark leaf 

 only an irregularly shaped film, of the finest texture, drawn 

 out toward the sloping margin of the leaf into a narrow 

 streak, with only a slightly thickened termination. The spi- 

 der then takes its place on its back on the irregular patch I 

 have described, holding itself in position by means of several 

 strong spines on the upper sides of the thighs of its anterior 

 pair of legs thrust under the film, and crosses its legs over its 

 thorax. Thus resting with its white abdomen and black legs 

 as the central and dark portions of the excreta, surrounded 

 by its thin web-film representing the marginal watery portion 

 become dry, even to some of it trickling off and arrested in a 

 thickened extremity such as an evaporated drop would leave, 

 it waits with confidence for its prey, a living bait so artfully 

 contrived as to deceive a pair of human eyes even intently 

 examining it." 



In Algiers is found a lizard which has at the corners of its 

 mouth bright red folds of skin which are of the same color and 

 shape as the blossoms of one of the desert plants. Insects 

 are deceived and come to feed upon the nectar and pollen, but 

 serve themselves as food for the lizard. These are examples 

 of what we may call alluring coloration and resemblance. 



