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Show 48 MR. R. I. POCOCK AND HON. N. C. ROTHSCHILD ON [Jan. 20, 6. On a new " Bird's-dung " Spider from Ceylon. By R. I. P o c o c k , F.Z.S., and the Hon. N. C. R o t h s c h i l d , B.A., F.E.S., F.Z.S. [Received November 18, 1902.] (Plate X .1) During a recent visit to Ceylon, the Hon. N. C. Rothschild, in company with Mr. E. E. Green, discovered a specimen of a Spider (Phrynarachne) imitating, for purposes of allurement and concealment, a patch of bird's-dung. A photograph of the spider resting upon the leaf in situ was obtained, and the leaf with its patch of web was brought home with the spider (PI. X . figs. 1, 2). The film of white web upon the leaf, with its irregular outline and marginal, often apically thickened projections, closely assimilates the splash of the fluid components of the excrement; while the spider itself, with its mottling of black and white, resting upon the centre of the film, with its legs tucked in, represents the semi-solid central core. So close, indeed, was the imitation that both observers were for a time deceived, until closer scrutiny revealed the true nature of the deceptive patch. It is commonly assumed that the purpose of this imitation is purely alluring or pseudepisematic. No doubt, however, it is an equally important procryptic factor, serving to protect the spider from various enemies, especially the wasps of the family Pompilidae. The spider, which appears to represent an undescribed species, may be named after one of its discoverers2. P h r y n a r a c h n e r o t h s c h il d i , sp. n . £ .- Colour. Carapace with a broad central black patch, with irregular lateral margin, extending from the eyes to the posterior slope, and forming an angular expansion on each side immediately behind the head; and with its posterior border passing into a median longitudinal stripe, continuous with a transversely arcuate black stripe which extends from the middle of the posterior slope of the carapace on to its lateral portion, breaking up into fainter patches separated by radiating pale bands; clypeus, sides of head, and area between central patch and lateral patches yellowish white. Mandibles yellow in basal half, with a large black patch, not reaching the fang, in the distal half in front, blackish brown beneath. Sternum mostly yellowish white, with a large subtriangular black patch, divided by a narrow pale line in its posterior half, and some black at the bases of the legs. Labium blackish, maxillae blackish internally, whitish externally. Palp with its femur white below, black above in its basal half; patella white, tibia and tarsus black, variegated with yellow patches. First and second legs with the coxae black, variegated 1 For explanation of the Plate, see p. 51. 2 Mr. R. I. Pocock takes the sole responsibility for the naming and description of the species. |