| OCR Text |
Show 378 REV. O. P. CAMBRIDGE ON NEW DRASSIDES. [June 2, digital joint is of ordinary form, rather large, and longer than the radial and cubital joints together. The palpal organs are well developed, but not very complex, consisting of several corneous lobes and processes of different forms. The falces are of moderate length and strength, a little projecting, and rather prominent near their base in front, where there are numerous long, coarse, prominent bristles. The maxilla are moderately long; they are broad and strong at and below the insertion of the palpi, which spring from a little more than halfway towards their extremities ; they are curved towards the labium, and broadly impressed across the middle of their front surface, and are rounded on the outer side and obliquely truncated on the inner side at their extremities. The labium is of an oblong-oval form, truncated at the apex ; the margins are impressed and somewhat constricted, giving to it, as well as to the same portion of structure in many other species of this genus, a peculiar appearance. The sternum, together with the labium and maxilla, are of a yellow- brown colour. The abdomen is of ordinary size, and narrow oblong-oval form, well clothed with hairs, and of a sooty black colour ; on the fore part of the upperside is a dull, obscure, yellowish-brown, elongate patch, followed by the ordinary six linear spots in two longitudinal opposed curved lines; these are, however, very indistinct; the underside is dull brownish, tinged with yellow. The spinners of the inferior pair are greatly the longest and strongest; the rest are very much smaller, especially those of the central pair, which are almost imperceptible. This Spider is very nearly allied to Prosthesima (Melanophora) lata (Cambr.), found in Palestine and also in Egypt; but Dr. L. Koch's opinion agrees with my own, that it is quite distinct. There is a slight difference in the structure of the palpal organs; the falces are less prominent at their base in front; and the spinners of the superior pair are, in P. tristicula, shorter than in P. lata. The generic distinction between Prosthesima and Drassus is slight, consisting chiefly in the position of the palpi with respect to the maxillae : in Drassus the palpi arise from the maxillae at or below the middle, never above it; in Prosthesima they issue at or above the middle, i. e. nearer to the extremities, but never below it. The maxillae also are more strongly impressed or constricted transversely in front near the middle. An adult male of P. tristicula was found by myself under a piece of rock near Alexandria, in April 1864. PROSTHESIMA LUGUBRIS, sp. n. (Plate LI. fig. 7.) Adult female, length 3 lines. This Spider is of ordinary form and general structure. The cephalothorax is deep black-brown, its highest point in the profile-line being at the beginning of the hind slope. The legs, palpi, falces, and other fore parts, except the sternum, are deep brown, the tarsi being reddish yellow-brown, and the abdomen black. |
