16 EDV. ELLINGSEN. 



Chthonius opticus, nov. sp. 

 Four large, elevated eyes, two on each side, scarcely a diame- 

 ter from each other, the anterior one a diameter from the front 

 margin; the eyes are placed on the anterior and posterior sides 

 of a small, dark-coloured protuberance, the anterior eye thus 

 looking forwards, and the posterior one backwards. 



Colour. - Céphalothorax, mandibles and palps pale reddish 

 brown, the sclerites brown; legs and the interstitial parts whitish. 

 Céphalothorax about as long as it is broad in front, nan-ow- 

 ing greatly backwards (in the male somewhat less so), the la- 

 teral margins slightly convex, the front margin straight, slightly 

 sinuated and depressed in the middle, with no traces of teeth. 

 The surface smooth and glossy with some long, pointed hairs. 

 Abdomen. 7'he surface of the sclerites somewhat uneven, 

 scarcely shagreened,- glossy, with some hairs along the hinder 

 margins. 



Palps smooth and glossy; the hairs strong and pointed, 

 somewhat longer on the inner side than on the outer. — Trochan- 

 tei- with no stalk, very short, the inner side very convex, short 

 and rounded behind. Femur with scarcely visible stalk, the 

 greater, central part of the inner side slightly concave, somewhat 

 thickened at the base and the extremity, nearly straight behind, 

 only slightly convex nearest the extremity. Tibia, as usual, 

 calyciform. Hand with hardly visible stalk, short and thick, 

 the inner side very convex, behind slightly convex, on both sides 

 passing somewhat abruptly into the lingers. Fingers twice as 

 long as the hand (in a younger, paler specimen even 2V2 times 

 as long), seen from above nearly straight, the moveable finger 

 distinctly shorter than the fixed one; in the vertical plane the 

 fingers are distinctly curved outwards, thus making an opening 

 between them when the fingers ai-e shut; the inner margins of the 

 fingers with separated, pointed teeth, on the fixed finger long 

 and narrow, on the moveable one considerably shorter; the inter- 

 stices between the teeth are at least three times the width of a tooth. 



