1880.] Ot' THE GENUS ARGYRODES. 339 



The palpi are rather short, the cubital and radial joints particu- 

 larly so ; the digital joint is large, and iu form very like that of 

 A. ulnlans, being devoid of the prominence so very strongly marked 

 in A. epeircc and others. The palpal organs are siuij)le in structure, 

 but prominent and well developed, with a short, closely fitting, 

 curved black spine near their anterior extremity. 



The eyes are in the ordinary position ; those of the hind central 

 pair are separated by a wider interval than those of the fore central 

 pair. 



'X\\&falces are neither very long nor strong ; and their direction is 

 a little forwards. 



The abdomen has its upper part produced backwards into a long, 

 somewhat tapering form, its extremity being slightly and im- 

 perfectly trifid, i. e. a blunt angular point on each side below, and a 

 third, rather longer, above and directed rather downwards ; its ground- 

 colour is of a dull brownish hue (though, the exam])les being in bad 

 condition, this may be different iu life), marked with a pattern of 

 brilliant silvery spots as represented in fig. 1/ ; the hinder part of 

 this pattern meets over the upperside ; there is also a single con- 

 spicuous silvery spot almost underneath on each side near the hinder 

 extremity, and another in the middle of the underside a little way 

 in front of the spinners. 



One tolerably perfect example, and some fragments of others, were 

 found among debris of the web of some large Epeirid, in Prof. 

 Traill's Amazons collection. 



Argyrodes amplifrons, sp. u. (Plate XXX. figs. 17 a', iV, e', 

 \7b\c',d',e',/',ff,k.) 



Adult male, length to the spinners scarcelj^ 1 line, and to the apex 

 of the abdomen 1|; in the adult female these measurements are, 

 respectively, 4 of a line and rather more than li line. 



This Spider is very nearly allied to Argyrodes obtusa, but may be 

 distinguished by several well-marked differences. The prominence 

 of the lower part of the caput (or inferior lobe) is much larger, still 

 more obtuse ; aud its upper part, when looked at from in front, is 

 more considerably cleft or bifid ; the space also between the cleft or 

 perforation which divides the lobe and the fore central eyes is more 

 prominent. The abdomen is more elongated, and more distinctly 

 trifid at its apex ; and the silvery markings are merely two small 

 patches of spots on each side, a small spot on each side rather under- 

 neath near the apex, another in the middle of the underside a little 

 way in front of the spinners, and two more in a transverse line behind 

 them. 



'J he palpi are very like those of A. obtusa ; and the general 

 colouring and appearance of the whole Spider is also very similar. 



The female has the anterior part of the abdomen much more 

 tumid, more perpendicular in its direction, and its apex more con- 

 spicuously trifid ; its whole surface is silvery, excepting a longi- 

 tudinal, not very distinctly defined, central longitudinal band on the 

 upperside extending quite to the apex, and a pointed stripe on the 



