OCR Text |
Show 1880.] OF THE GENUS ARGYRODES. 325 extremity on the upperside it is bisected by a tapering black stripe, which ends at the apex of the cone ; in the males this stripe is merely a short black line from which one or two vein-like branches issue obliquely on each side. The underside is black, or else black-brown deepening into black on each side ; the margins of this black portion are well defined, dentated, and extend a little way up the sides. The dentation of the margins differs in the sexes, as will be seen from the figures given ; in about a dozen examples of the female but very slight variation was apparent in the character of this dentation in that sex. On each side underneath, a little way in front of the spinners, are two round, shining, silvery spots in a transverse line. The palpi of the male are in general appearance very like those of A. epeira, Sim., and others ; the cubital joints are tumid and clavate, the radials short and spreading ; the digitals are large, with a strong prominence or lobe towards their extremity on the inner side. The palpal organs are moderately complex; and at their fore extremity is a rather prominent process, whose termination is bifid or distinctly cleft. An adult male and females of this Spider were contained in a collection of Spiders made in the Amazons of South America by Professor Traill, to whose kindness I am indebted for them. I have but little doubt that.it is the Spider described by Prof. Taczanowski, I. c. supra. In the form of the caput Argyrodes nephilee is very similar to A. rostrata, Bl. (Seychelle Islands); the anterior lobe of this latter species, however, is stouter, and the eyes of the hind-central pair are nearer to the summit of the occiput (vide Plate XXVIII. fig. 4 ci). The abdomen also is of quite a different form-less elevated, very obtuse at the apex, and with a distinct pattern on the sides (fig. 4 b'), this part in A. nephilee being immaculate. ARGYRODES ARGENTATA, sp. n. (Plate XXVIII. fig. 5.) Adult male, length T\ oi an inch; female considerably larger. This Spider is very closely allied to Argyrodes nephilee, Tacz., resembling it in general form, colours, markings, and appearance. It is, however, considerably larger ; the form of the caput differs in the more curved shape of its anterior segment, which is also rather longer in proportion to the posterior one; the hind central pair of eyes are also placed further up on the occipital part of the posterior segment, being thus considerably removed from a straight line with the lateral pair and fore-central eye on each side. The abdomen also is less elevated, and its conical point more obtuse ; it is of a similar brilliant silvery hue; its upper point slightly-tipped with brown, and a slender longitudinal central biack or deep-brown line on the upperside, sometimes enlarged in an angular form at one or two points, from each of which issues a short vein-like line. The central line or stripe seldom appears to reach the conical point of the abdomen, and does not differ in form or strength in the sexes. The legs are long, but not excessively so ; and their relative length is 1, 2, 4, 3 ; they are of a pale yellow colour, slightly tinged with |