426 Mr. J. Blackwall on newly discovered species 0/ Araneidea. 



other genera, where the animals periodically repeat the expan- 

 sion, leaving on the shells a succession of the varices and other 

 developments, which mark each successive expansion and de- 

 generation of the animal. 



XLIII. — Descriptions of six newly discovered Species and Charac- 

 ters of a new Genus 0/ Araneidea. By John Blackwall, F.L.S. 



Tribe Octonoctiliiia. 



Family TnoMisiDiE. 



Genus Thomisus, Walck. 



Thomisus Camhridgii. 



Length of the female ^ths of an inch ; length of the cephalo- 

 thorax J ; breadth -^-^ ; breadth of the abdomen /^y ; length of 

 an anterior leg /^ • length of a leg of the third pair \, 



The eyes are disposed on the anterior part of the cephalo- 

 thorax in two transverse^ curved rows, forming a crescent whose 

 convexity is directed forwards; the eyes of each lateral pair, 

 which are seated on a tubercle, are larger than the intermediate 

 ones, those of the anterior row being the largest of the eight. 

 The cephalo-thorax is large, convex, compressed before, rounded 

 on the sides, broadly truncated in front, depressed anteriorly, 

 still more abruptly so towards the base, and has a small indenta- 

 tion in the medial line ; the sides are of a brown colour marbled 

 with yellowish-white, and on the posterior part of each there is 

 an oval black patch, with its smaller extremity directed forwards, 

 whose outer margin is broken by a yellowish-white spot; the 

 lateral margins and a large band extending along the middle are 

 of a yellowish-white colour, the latter, immediately behind the 

 eyes, being tinged with brown and marked with spots and two 

 short, parallel streaks of a deeper shade ; a short, curved, black 

 line occurs near each side, below the lateral eyes, and the frontal 

 margin is fringed with a row of strong black hairs directed for- 

 wards. The falces are short, powerful, cubconical, vertical, and 

 of a yellowish- white colour in front ; the base, outer side, and 

 extremity having a brownish-black hue. The maxillae are some- 

 what pointed at the extremity, and inclined towards the lip, 

 which is triangular, but rounded at the apex ; and the sternum 

 is heart-shaped. These parts are of a pale brownish-yellow 

 colour, the base of the lip, that of the maxillae on the inner side, 

 and minute spots on the sternum, having a dark brown hue. 

 The legs arc provided with hairs and spines, two longitudinal 

 rows of the latter occurring on the inferior surface of the tibiae 



