THOKELL ON ARANE.E OF COLORADO. 481 



posterior central eyes are, however, larger, and the anterior central eyes 

 appear to be a little smaller than the rest. Seen from above, the hind 

 row of eyes is straight; the front row, seen from before, is also nearly 

 straight, very slightly curved backward. The four central eyes, of 

 which the anterior are placed on a prominent tubercle, form a trapezium 

 much broader behind than in front and as long as broad behind ; the 

 intervals between the eyes of the hind row are nearly equal, and 

 scarcely as large as half the diameter of one of thoso eyes, the interval 

 between the anterior lateral and ths anterior central eyes is at least 

 half as great again as that between these latter eyes and fully as great 

 as the diameter of a lateral eye ; the lateral eyes are contiguous. Ster- 

 num very large, triangular, with slightly rounded sides, and the apex 

 directed backward, broadly truncate in front, but little longer than 

 broad, slightly convex. Mandibles a little thicker than the thighs of 

 the first pair, nearly cylindrical, somewhat narrowed on the inner side 

 toward the apex, about 2^ times as long as broad; claw rather long and 

 slender. MaxiUie about half again as long as broad, nearly ovate, 

 broadly and obliqnely truncate on the inner side of the apex. Labium 

 transversal, slightly rounded at the apex. Palj)i slender, the tibial joint 

 nearly thrice as long as broad, the tarsal joint gradually tapering toward 

 the apex, longer than the two preceding joints together. Legs slender; 

 first pair longer than the second and fourth, which are nearly of the 

 same length. (In the only example examined, all the spines of the legs 

 are broken ofif ; on the tibire, but not on the femora and metatarsi, there 

 are distinct traces of spines lost.) Abdomen longer than broad, tapering 

 behind, nearly ovate; seen from the side, the vulva forms a short and 

 thick protuberance directed backward, strongly convex below, and 

 slightly bifid or two-toothed at the extreme apex : this protuberance 

 is about as thick as the posterior thighs and about half as long again 

 as thick; seen from below, the vulva is about as long as broad at the 

 base, tapering toward the blunt apex very uneven, with a narrow ridge 

 along the middle ; the slightly incrassated apex of this ridge appears 

 to reach a little longer backward than the rest of the vulva. 



Color. — Cephalothorax pale testaceous, with a fine black margin ; eyes 

 placed on black spots. Sternum of a sooty testaceous hue, with the 

 margins blackish ; labium blackish. Mandibles and maxilhc pale testa- 

 ceous, the claw of the former pale reddish. Palpi and legs pale testa- 

 ceous, somewhat darker toward the extremity ; the tibite show more or 

 less distinct traces of a sooty ring near the base, and the thighs traces 

 of such a ring toward the apex. The abdomen is above and on the 

 sides greenish-black or olive-colored, with pale yellowish markings ; it 

 has in front, on each side above, a broad short band, somewhat dilated 

 at the posterior end, which bands together nearly form a coarse /\ 

 above the petiolum; near the middle line of the back this marking is 

 followed by two pairs of short longitudinal lines, of which at least the 

 hindmost are curved outward; the posterior end of these lines is pro- 



