48 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



Mr. Henry O. Forbes relates a similar experience of deception. 1 He had 

 been allured into a vain chase after a large stately flitting butterfly (Hestia) 

 through a thicket of Pandanus horridus, when on a bush that obstructed 

 further pursuit he observed one of the Hesperidse resting on a leaf upon 

 a splash of bird dropping. He had . often observed small Blues at rest on 

 similar spots on the ground, and had wondered what the members of such 

 a refined and beautifully painted family (Lycenidae) could find to enjoy in 



food so seemingly incongruous for a butterfly. He approached 

 Mimicry w j^ g en ti e steps and ready net to see, if possible, how the present 

 "", individual was engaged. It permitted him to get quite close, 



and even to seize it between his fingers. To his surprise, however, 

 part of the body remained behind ; and in adhering, as he thought, to the 

 excreta it recalled an observation of Mr. Wallace's on certain Coleoptera 

 falling a prey to their inexperience by boring in the bark of trees, in whose 

 exuding gum they became unwittingly entombed. He looked closely at the 

 excreta to find if it were glutinous, and finally touched it with the tip of 

 his finger. To his delighted astonishment he found that his eyes had been 

 most perfectly deceived, and that the excreta was a most artfully colored 

 spider lying on its back, with its feet crossed over and closely ad pressed 

 to the body. 



The appearance of recent bird droppings on a leaf is well known. Its 

 central and denser portion is a pure white chalk like color, streaked here 



and there with black, and surrounded by a thin border of the 



/"V * .i-l_ 



Ornitho- (] r j e( j up more fluid part, which, as the leaf is rarely horizontal, 



scatoides 



deci i ns ^ en runs a little way towards the margin. The spider observed 



by Mr. Forbes, like that seen by Mr. Webster, was pure chalk 

 white in general color, with the lower portions of its first and second pairs 

 of legs and a spot on the head and abdomen jet black. 2 It had woven 

 on the surface of the leaf, after the fashion of its family, an irregularly 

 shaped web of fine texture, which was drawn up towards the sloping mar- 

 gin of the leaf into a narrow streak, with a slightly thickened termination. 

 This form, as described by Mr. Forbes, was doubtless determined by 

 the concavity of the leaf, and the facility which the slightly turned up 

 edges gave for making good points of adhesion, at the same time leaving 

 a little space between the netted spinningWork and the leaf's surface over 

 which it was stretched. According to Mr. Forbes, the spider takes its place 

 on its back upon this irregular spinningwork, holding itself in position by 

 means of the spinal armature of the legs thrust underneath the web, and 

 crosses its legs over its thorax. I do not remember to have observed any 

 Thomisoids in this position, but have always seen them crouching with 

 back upward when not using a web. I would suppose that if they used 



1 A Naturalist's Wanderings in the Eastern Archipelago, 1885, pages 63, 04. 



2 Rev. O. P. Cambridge describes it as Ornithoscatoides decipiens. 



