276 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



of the clypeus; the siderear eyes are much larger and are upon tubercles overhanging the 

 Bides 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 (HBNTZ). Plate XXVII, Fig. 7. 



1847. Oyllopoda cavata, HENTZ J. B. S., v., 466; Sp. U. S., p. 104, xii., 3; xx., 21. 



1875. Hyptiotes Americans, WILDER . . Popular Science Monthly, Sept., p. 2 (The Tri- 

 angle Spider). 



1884. Hyptiotes cavatus, EMERTON . . . N. E. Ciniflonidae. 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. 



FEMALE: Total length, 5 mm.; cephalothorax, 2 mm. long, 1 mm. wide; abdomen, 2.5 

 mm. long, 2 mm. wide. 



CEPHALOTHORAX : An irregular oval, rounded at the margin, steep, truncated at the 

 base, which shelves 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 maxillae, 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 procurved, 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. 



LEGS: 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 Ciniflonidac, in this 

 respect uniting the Orbweavers with the Tubeweavers. The color is yellow or olive brown. 



ABDOMEN: 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 



