276 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
of the clypeus; the siderear eyes are much larger and are upon tubercles overhanging the 
sides of the face, separated from the sidefront by a space greater than that which sepa- 
rates them from the midrear, The other six eyes are placed far back upon the face. The 
clypeus is wide. The legs are 1, 4, 2, 3; short, stout, I and II especially so; the fourth leg 
is curved and provided with a calamistrum, The abdomen is oval, with highly arched 
dorsum symmetrically covered with low conical humps on the margins, and rounded at 
the base and apex, the latter overhanging the spinnerets which are provided with a cribel- 
lum. The male resembles the female in general structure and color. The abdomen pre- 
sents the same lumpy appearance, and is pubescent. The radial joint is stout, somewhat 
curved; the digital joint extremely long, canoe shaped, and complex. 
No. 122. Hyptiotes cavatus (Henrz). Plate XXVII, Fig. 7. 
1847. Oyllopoda cavata, Hentz... . + J. B. S., v., 466; Sp. U.S. p. 104, xii, 3; xx., 21. 
1875. Hyptiotes Americanus, WitpER. . Popular Science Monthly, Sept., p. 2 (The Tri- 
angle Spider). 
1884. Hyptiotes cavatus, Emmrvon . . . N. BH. Ciniflonidee. Trans. Con. Acd. vii., 457 ; ii., 2. 
1889. Hyptiotes cavatus, McCook . . . Amer. Spiders and their Spinningwork, Vol. I. 
1889. Hyptiotes cavatus, Marx. . . . . Catalogue, p. 553. 
Frmatr: Total length, 5 mm.; cephalothorax, 2 mm. long, 1 mm. wide; abdomen, 2.5 
mm. long, 2 mm. wide. : 
CrpHatornorax: An irregular oval, rounded at the margin, steep, truncated at the 
base, which shelyes sharply downward from the fosse, which is a semicircular indentation 
upon the upper part of the incline; cephalic suture distinct, but the pecular structure of 
this part of the body makes it somewhat difficult to distinguish between the head and the 
corselet itself; color dark brown to blackish, with grayish yellowish pubescence. Sternum 
(Fig. 6b) cordate, widest at the base; sternal cones distinct; color dull yellow, with grayish 
white pubescence, especially at the edges; raised in the middle; the labium rounded at the 
tip about half the height of the maxille, which are obtusely triangular at the tips, as wide 
as long; color dull yellow. 
Eyes: Six of the eight placed far back upon the face; the ocular quad very wide in 
the rear, narrow in front, and the sides little more than half the rear, presenting the 
form of an isosceles triangle truncated at the apex; MF separated by about one diameter, 
SR by a space equal to about four times the area of MF; side eyes as widely separated as 
MR, SF extremely small and placed well to the front just over the outer edge of the 
mandibles, about 2.5 diameters from the margins of the clypeus; these eyes extremely 
small, so much so that Hentz failed to observe them, and described the spider as having 
only six eyes; SR much larger than SF, are indeed the largest of the entire group, located 
at the extremities of the optical area upon the upper edge of the face, which they over- 
hang. The clypeus is wide from the middle point to MF, being about three times the area 
of the latter; the group of eyes thus described form two rows, of which the front row is 
much procuryed, the rear row slightly procurved; of the rear row the distance between 
SR and MR is about one-third less than the space separating MR, and somewhat less than 
the distance between SR and SF. 
Leas: 1, 4, 2, 3; short, stout, especially I and II; abundantly clothed with bristles 
and hairs, and with short spines; the tarsus with one Epeiroid claw; the metatarsus of 
leg-I is curved, and provided along its exterior surface with a row of curved hairs known 
as the calamistrum, which characterizes Uloborus and some species of Ciniflonide, in this 
respect uniting the Orbweavers with the Tubeweayers. The color is yellow or olive brown. 
Axspomen: Oval; the dorsum highly but not evenly arched, curving downward to the 
spinnerets, which are slightly overhung by the apex; on the base in front are two low 
humps, and along the sides is a series of three low conical elevations, which give the 
dorsum a roughened appearance; the color varies, is yellow or yellowish brown, streaked 
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