THORELL ON ARANE^E OF COLORADO. 509 



what transverse, rounded in the sides, also slightly rounded behind, 

 and limited by a brown margin on the sides and behind, but without 

 any distinct sculj^ture. 



Color. — Cephalothorax black, with a pale brownish, longitudinal, middle 

 band, reaching at least to the hindmost eyes, behind which it is some- 

 what constricted, and nearly as broad in front as the area of the poste- 

 rior eyes, gradually tapering backward, geminated by a fine black line, 

 and covered with grayish-white hair. The sides of the cephalothorax 

 are clothed with brownish hair, more grayish toward the margins. 

 Sternum black or brown, covered with short grayish-white hair. Man- 

 dihles brownish-black, with indistinct yellowish spots; maxillae yellowish, 

 blackish along the middle; labium yellowish, blackish at the base. 

 Palin and legs of a dull brownish-yellow color with blackish rings; the 

 coxa3 are yellowish beneath, especially at the base ; the thighs, which 

 sometimes are blackish beneath, have three or four broken rings, formed 

 of irregular black spots ; the anterior thighs have, moreover, a yel- 

 lowish longitudinal line on the outer side; the tibitB have two or three, 

 the metatarsi three blackish rings. The back of the abdomen is black- 

 ish toward the sides, rusty-brown along the middle, with a black spot 

 on each side in the margin of this broad rusty-brown band, or area, be- 

 tween the middle of the back and the anus ; this area is covered with 

 grayish-white hair, forming a broad longitudinal band all along the 

 back, and a row of small spots of the same color along the lateral mar- 

 gins of the band. The belly is grayish-brown, covered with grayish 

 hair ; the mamillce are deep black, paler at the apex. 



Length of body 7, of cephalothorax 1^ millim. ; breadth of same 2f 

 millim. Legs: I 11, II lOi, III 10.]-, IV 15 millim.; patella + tibia IV 4§ 

 millim. 



Male. — The male closely resembles the female in form, with exception 

 of the sexual organs. The cephalothorax is as long as tibia + patella of 

 the second pair. The patellar joint of the palj)i is, seen from above, 

 cylindrical, rounded in front, not fully double as long as broad. The tib- 

 ial joint is a little broader, and, at least when seen from the side, slightly 

 longer than the patellar joint, gradually, but very slightly, thickened 

 toward the apex; the tarsal joint is fully as long as the two preceding- 

 joints together, about double as broad as the tibial joint, nearly ovate, 

 but strongly narrowing toward the apex, very convex ; the genital bulb is 

 nearly circular, elevated into a very high, almost conical, tubercle at the 

 base ; from the anterior, excavated side of the blunt apex of this tubercle, 

 more inward, proceed two strong spines ; the inner, which is by far the 

 longest and strongest, and tapering toward the obtuse apex, is directed 

 forward and outward and curved upward and slightly backward, thus 

 separated from the anterior lower part of the bulb by a great empty 

 space ; the other spine, which issues in front of the first named, is much 

 shorter and slenderer, more pointed, directed downward aiul outward, 

 with the extreme apex curved inward. In front of the elevated basal 



