196 ARANEIDEA. 
or a little clavate. Radial joint considerably longer than the cubital, of a curved form (in profile), 
furnished with coarse hairs and bristles; a small obtuse red-brown prominence at its fore extremity 
beneath ; another in front of it, 2. ¢ at the side of the joint, broader, stronger, and rounded at its 
extremity, and close in front of this is a long, strong, somewhat flattened apophysis, about half the length 
of the joint; this apophysis widens rapidly, and its hinder corner is considerably produced, ending in a 
furcate form, its inner (or fore) corner has a sharp dentiform point, and there are two other dentate points 
on the fore margin of the apophysis between it and the furcate extremity. Digital joint large, oval, 
furnished with coarse hairs, those on the anterior portion of equal length and densely grouped in a 
tuft-like mass; at its base on the outer side the digital joint is produced, with an obtuse or rounded 
termination of a semicorneous appearance, and thence the whole of the outer margin of the joint is 
corneous-looking, as though bound round by an adherent spine. ‘The palpal organs are not very complex, 
but greatly developed ; a large semicorneous-looking septum or lobe, flattened on the outer side, convex on 
the inner, runs, kecl-like, from end to end of these organs, its profile being somewhat circularly rounded, and 
its margin having a closely-fitting red-brown somewhat filiform spine all round it ; this spine issues from 
the base (or hinder extremity) of the palpal organs and tapers rapidly, ending at the anterior extremity 
of the septum, along the outer side of which, near the outer margin of the joint, are two long, obtuse- 
ended, corneous processes. 
Falces long, strong, tapering, slightly divergent, furnished with numerous dark red-brown granulations and 
coarse bristles in front. The inner margin of the falces is canaliculate, with teeth on each edge. 
Sternum of a narrow-oval form, ending behind in a tolerably sharp though short point between the coxe of 
the fourth pair of legs, which are well separated by rather less than half a diameter’s interval. 
Abdomen elongate-oval, subcylindric, generally luteous-yellow, but duli orange-yellow on the fore half of the 
upperside, clothed with pale grey hairs. Spinners compact, prominent, of normal length and strength, 
the inferior pair longest. 
Hab. Guatmmaua, Yzabal (Sarg). 
THWAITESIA, Cambridge. 
Thwaitesia affinis. 
Thwaitesia affinis, Cambr. P. Z. S. 1882, p. 431, t. 31. fig. 8a. 
The female only of this spider (from the Amazons) has been described, and a small 
portion of its structure figured (J. ¢. supra). It seems worth while, therefore, to give, 
along with a description of the male, figures illustrating the general appearance of this 
delicate and lovely species. 
In colour and markings the male resembles the female. The cephalothorax, legs, palpi, falces, maxille, 
labium, and sternum pale yellow; the anterior extremity of the tibia and metatarsi of the first and fourth 
pairs of legs tinged with orange-brown. Abdomen of a duller yellow hue than the rest, spotted above and 
on the sides with largish pearly-silver plate-like spots, leaving an elongate bare stripe along the middle 
of the fore-half of the upperside; the conical elevation of the upperside is far less in height than in the 
female, the abdomen being thus much longer in proportion to its height in the male. 
The palpi are tolerably long; the cubital joint slightly bent, and, among other hairs, has a long bristle at the 
fore extremity on the upperside; the radial joint is nearly double the length of the cubital, and increases 
gradually from the posterior to the anterior extremity, it is furnished with long, slender, pale bristly 
hairs; digital joint oval, of moderate size, its base equalling the fore extremity of the radial joint in 
width. Palpal organs moderately complex, consisting of a large central corneous process, and with a 
black, circularly curved, tapering spine rnnning from another process near the base round the hinder part 
and lower side. There are also two or three small corneous processes at the fore extremity immediately 
beneath the fore end of the digital joint. 
The legs are 1, 4, 2, 3—1 and 4 being greatly longer than the rest. 
Hab. Panama, Bugaba (Champion). 
This spider is (as remarked J. ¢. supra) very nearly allied to the Ceylon species, 
