8 Proceedings of the Royal Irish Academy. 



the posterior intermediate eyes, between which there are two short 

 confluent streaks of the same hue. The falces are short, cuneiform, 

 vertical, and of a red-brown colour, being palest at the base, in front, 

 where there is an irregular yellowish-white spot. The maxill® are 

 obliquely truncated at the extremity, on the outer side, and inclined 

 towards the lip, Avhich is triangular, but rounded at the apex. These 

 parts are of a red-brown colour, their extremities having a yellowish- 

 brown tint. The sternum is heart-shaped, glossy, and of a pale-yellow 

 hue. The legs are provided with hairs and spines, two parallel rows 

 of the latter occurring on the inferior surface of the tibiae and meta- 

 tarsi of the first and second pairs, and a few conspicuous ones on the 

 anterior side of the former ; they are of a pale red-brown hue, with 

 yellowish- white annuli more or less perfectly formed, those on the 

 base of the third and fourth pairs being much the broadest ; the first 

 and second pairs, which are longer and more robust than the third and 

 fourth pairs, are equal in length, and the third pair is the shortest ; 

 each tarsus is terminated by two curved, minutely pectinated claws. 

 The palpi, which are short and slender, resemble the legs in colour, 

 and have a small curved claw at their extremity. The abdomen is 

 oviform, moderately convex above, projecting a little over the base of 

 the cephalothorax, and has a few short hairs distribiited over its 

 surface ; it is of a whitish hue, with a large dark-brown band, freckled 

 with minute white spots, extending along the middle of the upper 

 part to the coccyx ; this band is irregular in outline and broadest about 

 the middle ; it then tapers to its extremity, which has a tinge of red, 

 and projects short parallel streaks from each side ; a white line, which 

 passes from the anterior part of the band along the middle, is crossed 

 near its extremity by two short curved lines of the same hue, and is 

 followed by two white spots, the anterior one being the larger ; the 

 band also comprises five depressed dark -brown spots ; the three 

 anterior ones describe an angle whose vertex is directed forwards, and 

 the other two are parallel to its base ; the sides are marked with dark- 

 brown confluent spots that form oblique rows ; a pale-brown band, 

 which tapers to its extremity, extends from the yellow branchial oper- 

 cula along the middle of the under part to the spinners, the superior 

 and inferior pairs of wliich organs are spotted with black at the 

 base ; the sexual organs are well developed, and have a pale red- 

 brown hue. 



Grenus Olios, Walck. 



Olios validus, n. sp. [Isopeda, L. Koch]. Plate 1, fig. 7. 



Length of the female, \\\s inch; length of the cephalothorax, iV; 

 breadth, -re ; breadth of the abdomen, -h^j ; length of a leg of the second 

 pair, 2xV ; length of a leg of the third pair, li^y. 



The eyes are disposed on the anterior part of the cephalothorax in 

 two transverse nearly parallel rows, the anterior row, which is the 

 shorter, being situated immediately above the fi'ontal margin ; the 



