38 Rev. O. 1*. Cambridge un some new 



The j)alj)i are short and tolerably strong ; their colour is 

 similar lo that of the legs, and they are also furnished with 

 hairs and numerous spine-like bristles, the terminal claw being 

 slightly curved and finely pectinated. 



The fiilces are strong, ratlicr prominent near their base in 

 front, where they are also thickly marked with somewhat 

 quadrate dull yellow-brown blotches ; and thence to their 

 extremities on the inner surface there are numerous strong 

 bristles, some of which are of a spinous character. 



The aternum is of a short oval form, truncate before and 

 produced into a point behind, at the extremity of which as 

 Avell as opposite the insertion of each of the first three pairs of 

 legs is a small tubercle. 



The abdomen is quite flat and of a subtriangular form, the 

 apex forming the hinder extremity, which is bifid or broadly 

 notched. Each of the numerous pentagonal shining compart- 

 ments into which its surface (both above and below) is 

 map})ed out has a large central oval depression, made more 

 conspicuous by a brown spot ; the fore margin is slightly 

 scalloped, hollow in the middle, enlarging and rounding on 

 either side to the fore corner, which is armed with a strong, 

 deep, blackish red-brown, slightly curved, but not very sharp- 

 pointed spine; between this spine and the central hollow part 

 of the fore margin there are, on each side, at the salient points 

 of the scalloped border, four small, brown, blunt-pointed tuber- 

 culiform spines ; the whole of the margins of the abdomen, 

 both above and below, are thickly studded with minute round, 

 brown and shining tubercles, each of which bears a small 

 bristle ; these bristles are not prominent, but sessile, and are 

 thus scarcely visible, except under a magnifying-glass ; the 

 ribs which divide the shining pentagonal plates or bosses are 

 also studded with, for the most part a single row of, very 

 minute, brown, shining, bristle-bearing tubercles. 



This remarkaljle spider, which in its general appearance 

 bears some resemblance to a small butterfly, shows a strong affi- 

 nity both to the Gasteracanthides and to Arcys^ and is evi- 

 dently a transitional form ; but as it appears to me to be more 

 nearly allied to the latter than to any of the groups of Gastera- 

 canthides, not only by its general form, but by the peculiar 

 structure of the cephalothorax, I have placed it along with 

 Arcys in the family Arcydes ; it differs, however, remarkably 

 from Arcys in the general character and lengths of the legs, 

 as also in the details of the abdominal scutum ; for which and 

 other reasons it has been necessary to constitute a new genus 

 for its reception. 



A single example was contained in a small collection of 

 spiders from Madagascar, purchased of a London dealer in 1876. 



