272 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
Eyes: Ocular quad (5b) with little elevation; length greater than width, the front 
slightly narrower than the rear. The eyes of the group subequal; side eyes upon a low, 
blackish tubercle; SF larger than SR, and nearly equal to MF, from which they are separated 
by a space about twice that of the distance between MF. MF are separated by about 
1 diameter, MR by 1.5. The front eye row is recurved, the rear row almost aligned. The 
clypeus height about 1.5 diameter of MF. 
Lees: 1, 2, 4, 3; yellow, the joints with black median and apical annuli. Numerous 
long, black spines, with black bases, which give the legs a mottled appearance, and long, 
thin, aculeate bristles. The tibia of leg-II without any special clasping organs; but on the 
inside of the femur there is a more numerous row of spines. The mandibles are conical, 
brownish, strong, widely separated at the tips. The fang (5c) strong, smoothly curved, 
scarcely reaching to the maxille when folded; the interior row of teeth numbers about 
four. The palps are rather long; the digital joint (5d) but little longer than the radial ; 
the cubital still shorter. A strong spur issues from the base of the digital joint. 
Azspomen: Rectangular ovate; color cretaceous yellow, mottled with black; strongly 
pubescent; an irregular folium, formed principally by black hairs, marks the dorsum. 
Disrripution: Pacific Coast. I have three examples of the male of this species, 
received from and dedicated to the late Mr. John Curtis, of Oakland, California. This 
species, when first received, was placed by me with Pachygnatha, and as such figured here. 
It now appears to me, especially from the legs, and narrow clypeus and maxille, to be 
wrongly so placed. ; 
The species of Pachygnatha are not easy to separate by striking characteristics. P. 
brevis, which I have made the type, may be noted as the largest, by its bright colors, by 
the lumpy and punctured appearance of the head. The male mandible has at the lower 
interior angle (Plate XXVIIL., 2) a long tooth, with three small teeth around its base. P. 
Dorothea resembles brevis, but the female is distinguished by a blunt cone or hump on 
the exterior of the mandible (Plate XX VI. 3a), and the male mandible has no such tooth 
as in brevis. P. xanthostoma, female, is a rather smaller species, and the male may be 
at once noted by a short, projecting, toothlike spur on the outer margin of the apex (Plate 
XXVL., 8a). P. tristriata is at once separated by the abdominal markings of longitudinal 
stripes; by the longer oval of the abdomen, and the epigynum placed near the ventral 
base, close to the gills, instead of near the middle, as with the above species. P. autum- 
nalis is the smallest, has rather darker colors, and in both sexes a head much elevated, 
and the side outline of mandible is nearly straight, instead of rounded. The central quad 
of eyes is raised well up, the midrear pair above the vertex. The hump upon the man- 
dibles of P. Dorothea is a good distinguishing mark. 
Genus ULOBORUS, Larrertin, 1806. 
The species of this genus are distinguished by an oval cephalothorax, nearly as 
wide in the anterior as the posterior part, whose sides round with nearly equal width to the 
face. The corselet is high, well arched, but somewhat flattened upon the top; the corselet 
grooves distinct, the cephalic suture well marked. The head is wide, somewhat quadrate, 
slightly elevated above the corselet. The sternum is much longer than wide, of about 
equal width throughout, except at the apex. The labium is about half the length of the 
maxillz, which are somewhat longer than wide. The genus is particularly distinguished 
by its eyes, which can hardly be divided into the three groups characteristic of the 
Orbitelarize, and appear to be arranged simply in two rows. The ocular quad has the mid- 
front eyes upgn a rounded eminence, is much wider behind than in front; the intervening 
space between the sidefront and midfront eyes corresponds with that of Epeira; the side 
eyes present the most distinctive peculiarity, being widely separated, the intervening space 
greater than that between the midfront and sidefront eyes. The front row of eyes is some- 
