Arachnida. 



8589 



Maxillae like the falces in colour ; long, strong, obliquely truncated 

 at the top on the outer side, and slightly inclined towards the 

 labium, which is broad, short, semicircular, and of a sooty brown 

 colour. 



Palpi rather long, moderately stout, similar to the falces and 

 maxillae in colour. Cubital joint double the length and stout- 

 ness of the radial : the latter joint has the upper extremity pro- 

 duced into a longish tapering kind of spur; this projection is 

 nearly straight, and has a dark-coloured pointed tip ; it is directed 

 slightly outwards, over the basal half of the digital joint, but 

 does not lie flat upon it as in many other species. Digital 

 joint of moderate size and hairy. Palpal organs highly deve- 

 loped and prominent, but not very complicated. A long, strong, 

 black spine, enveloped in transparent membrane, issues from 

 their outer side, and, curving rather forwards and downwards, 

 forms a large loose coil on their outer and under side : the end 

 of this spine is very fine and filiform, and projects among a 

 mass of semitransparent membrane on the outside, near about 

 the middle of the length of the digital joint. 



Abdomen moderately convex above, glossy, and projecting over the 

 base of the cephalothorax. Colour dark sooty brown, with a 

 greenish tinge. It is sparingly clothed with dark hairs. 



The female differs from the male in being rather larger, and in 

 wanting the tubercular elevations and cusps on the frontal corners of 

 the cephalothorax. I met with this very remarkable, though minute, 

 spider in tolerable abundance on iron railings at Bloxworth, in April 

 and May, 1862. It was commonly to be found in an inverted posi- 

 tion, in an irregular web spun in the angles of the posts and upper 

 rails. It may at once be distinguished from others of its genus by the 

 broad, flat and almost circular cephalothorax, as well as by the two 

 frontal eminences, which give it a very striking appearance. Mr. 

 Blackwall tells me that it is allied to Theridion sulcifrons, Wider, a 

 species I have never yet seen. Except for Mr. BlackwalPs opinion 

 to the contrary, I should have unhesitatingly included it in the genus 

 Walckenaera, to which it appears to be as nearly allied as to the 

 genus Neriene. 



Walckenaera trifrons. 



Male, adult. Length 1-eleventh of an inch. Length of cephalo- 

 thorax 1 -twenty-fourth. Relative length of legs, 4, 1, 2, 3. 



