THORELL ON ARANE.E OF COLORADO. 511 



four posterior eyes is a little longer than broad in front, mucb (the di- 

 ameter of one of the largest eyes) broader behind than in front ; the 

 space between these two eyes is a little greater than their diameter, 

 that between them and the hindmost eyes double the diameter of one of 

 these latter eyes. The mandibles are about 2J times as long as broad? 

 slightly convex longitudinally ; the posterior margin of the claw-furrow 

 is armed with three rather small teeth, the anterior with two. The legs 

 are slender, of moderate length, the fourth pair rather more than 4 times 

 as long as cephalothorax ; the tibite of first pair have 2. 2. 2. spines be- 

 neath and 1. in front; those of the second pair 2. 2. 2. beneath and 1. 1. 

 in front. The ahclomen is of the ordinary form, rather inversely ovate. 

 The vulva is a large and corneous area, which behind shows two deep, 

 semi-elliptical or rounded fove?e, continued forward as two short, nearly 

 parallel furrows ; between these furrows and the fovese is a long sep- 

 tum, very narrow between the furrows, gradually dilated backward quite 

 to the end of the vulva, where it is truncated, and about as broad as the 

 foveae, and fills up the space between the lateral margins of the vulva 

 behind ; along the middle it shows a furrow, and it is also gradually di- 

 lated forward at the anterior apex, and there provided with a wedge- 

 shaped furrow or depression ; the anterior (not depressed or excavated) 

 part of the vulva thus resembles a narrow |V| ; the posterior part, which 

 is the longer (at least sometimes), is somewhat transversal, nearly ellip- 

 tical, and more than double as broad as the anterior part. The margins 

 which limit the sides of the posterior part of the vulva (the fovere) are 

 incrassated behind, terminating in a low, broad tubercle on either side 

 of the end of the septum. 



Color. — Cejyhalofhorax black, with a longitudinal, rather broad, middle 

 band strongly constricted behind the eyes, narrowing backward from 

 the middle, and there geminated by a fine black line ; toward the mar- 

 gins, the cephalothorax shows a row of three or four larger, more or less 

 distinct, supramargiual spots. The sternum is deep black, the mandibles 

 blackish, with dusky testaceous spots. The paljn and legs are black? 

 with rusty-brown rings or patches and streaks; the coxiie are somewhat 

 paler beneath, at least at the very base ; the thighs have two long rusty 

 brown patches above, geminated by a black longitudinal line, and a more 

 or less distinct patch between them, the anterior ones also a pale line 

 along the outer side; the patellae are brownish above, with a middle, 

 black, longitudinal line ; the tibiie have two, more or less distinct, rusty- 

 brown lings, geminated above by a black line ; the metatarsi have two 

 distinct, broad, rusty-brown rings; the tarsi are rusty- broyN'n, blackish 

 at the fipcx. The abdomen is brownish-black, the belly of a sooty-gray 

 color. The vulva is brown. The superior mamill<v are rusty-brown, the 

 inferior black. 



Length of body 7, of ceidialothonix 3A millim. ; breadth of cephalo- 

 thorax L>| millim. Legs: I lOi, II and iff lOj, IV 15 millim.; patelhi -f 

 tibia IV somewhat more than 4 millim. 



