DESCRIPTION OF GENERA AND SPECIES. 221 



Female: Total length, 16 mm.; cephalothorax, 6 mm. long, 4.5 mm. wide; abdomen, 

 11 mm. long, 8 mm. wide at the middle, 4 mm. at the base, narrowing to 2 mm. and less 

 at the apex. The spider is easily distinguished from its two largest indigenous congeners 

 by tlie peculiar serrated form of the abdomen, and by the brilliant silvery and beautiful 

 yellow markings on the basal half of the dorsum. The metallic lustre is caused by masses 

 of silvery hairs which closely thatch the cephalothorax and abdomen. This sheen does 

 not show in alcohol, and the specimen requires to be dried in order to bring it out in any 

 degree. 



Cephalothorax : A long oval ; corselet rounded at margins, indented at base, flat, with 

 a deep circular fosse; corselet grooves distinct; cephalic suture well marked; ground color 

 blackish brown, with a yellow band along the margin of the corselet and a yellowish 

 median strip both on corselet and caput; the whole is covered thickly with silvery hairs, 

 which give a shining metallic appearance; the caput is quite pointed at the base, flattened 

 in front, and much widened at the face, covered also with silvery hairs; sternum shield 

 shaped, wide across the front, obtusely triangular at the point ; the field dark brown, glossy, 

 but covered thickly along the margins with yellowish or silvery white hair ; on the anterior 

 portion strong black bristles ; raised in the middle and in front ; with decided sternal cones. 

 Labium high, subtriangular ; maxillse longer than wide, gibbous. 



Eyes: Ocular quad on an elevation distinctly depressed in the middle, thus separating 

 the front and rear parts into two eminences on which the eyes are seated ; the quad much 

 longer than wide, decidedly wider behind than in front ; eyes not greatly diflerent in size, 

 but MF slightly larger, separated by about 1.75 to 2 diameters; ME by 2.5; side eyes on 

 high tubercles; MR much larger than MF, the two barely contingent; MF separated from 

 SF by a little more than their area, or 1.5 the interval of IMF; MR from SR by a space 

 much greater than divides MF and SF. Clypeus height 3.5 to 4 diameters MF; front row 

 slightly, rear row much procurved. 



Legs: 1, 2, 4, 3; yellow, with broad apical and median dark brown annuli ; legs-I, III 

 in many specimens darker than II, giving indeed the impression of dark brown legs with 

 yellow annuli ; freely provided with bristles and long, thin, yellowish spines, and thickly 

 covered with silvery white pubescence ; palps yellow, with a touch of brown on the ter- 

 minal joints, which are tolerably well provided with dark spines and gray bristles; man- 

 dibles conical, dark brown, flecked with yellow, glossy and slightly pubescent. 



Abdomen: Rectangular ovate widest about the middle, narrowing towards the base, 

 which is cut squarely across, and narrowing also towards the apex, which terminates in a 

 pointed tubercle like a caudal part that extends quite beyond the spinnerets. The dorsum 

 ratlier flat, but the surface much broken ; divided into two well marked parts about the 

 middle by a thick armor of silvery hairs, with which the base is clothed ; at the narrowed 

 anterior of the base are two short, distinct, rounded tubercles ; the line of separation above 

 noted is marked on either side by a similar but smaller tubercle, and there is another in 

 the middle of the dividing line ; the apical part is divided along its edge on each side into 

 two rounded projections or lobes, leaving the apex extended posteriorly from the middle as 

 a fifth lobe. The silver armor extends downward along the median line by a narrowing 

 band somewhat rounded before it terminates ; on either side of this the space is a yellow 

 and blackish brown folium, through which branching lines extend towards the apex. The 

 venter is beautifully marked by a truncated pyramid of brownish yellow, thickly studded 

 with short blackish bristles, and bordered on both sides and behind by a silvery band, the 

 posterior part being the widest ; between this and the spinnerets is a patch of brown 

 flanked on either side by a blackish brown belt, which entirely encompasses the spinnerets, 

 at whose base there is a somewhat broken band of yellow ; the sides along either flank of 

 the ventral folium are black, flecked with brown, in the midst of which are many bristles, 

 ■whoise bases are glossy, chitinous, well raised above the surface, and when the shafts are 

 broken off add to the glistening appearance of the surface. The epigynum (Figs. Ic-d) has 

 a marked resemblance to that of A. argyraspis ; the atriolum is rather narrow, the scapus 

 rising from its base in a wide yellowish belt, which is indented at the base, and projects at 

 the middle into a scapus, which is depressed in the middle but highly arched, and widened 



