DESCRIPTION OF GENERA AND SPECIES. 267 



GENUS PACHYGNATHA, SUNDEVALL, 1823. 



Pachygnatha, like Tetragnatha, is distinguished by ita strong, elongate, curved jaws, 

 widely separated at the apex, and armed with formidable teeth. It is distinguished from 

 Tetragnatha, on the other hand, by an ovate abdomen, but little longer than wide. The 

 cephalothorax is oval, its skin hard and glossy ; the caput rounded and elevated above 

 the corselet, the grooves and cephalic suture distinct. The sternum is longer than wide, 

 decidedly aculeate at the apex, with distinct sternal cones ; wide at the base. The labium 

 is long, wide at the base, more than half as long as the maxillae, which are decidedly 

 longer than wide, a little compressed at the shank, convex on the outer margin, and 

 inclined toward each other. The legs are in order of length 1, 2, 4, 3, nearly all without 

 ordinary spines, but freely clothed with soft, long, aculeate bristles. The palps are long, 

 and armored as the legs. The mandibles are formidable, elongate, resembling those of 

 Tetragnatha. The eyes are in three groups, the central quad upon a high eminence; the 

 side eyes upon tubercles less elevated ; the space between the midfront and sidefront eyes 

 is somewhat greater than the area of MF, twice and more the intervening space thereof, 

 as in Epeira. The clypeus is extremely high, being more than 1.5 times the area of MF, 

 as in Theridioid genera. The front eye row is slightly recurved, the rear row more or less 

 procurved. 



No. 113. Pachygnatha brevis KEYSERLING. Plate XXVI, Figs. 9, 10 ; XXVIII, 2. 



1882. Pachygnalha tristriata, 1 KEYSEKLING . Neue Spinn. Amerik., iv., 209, Zool. Bot. Ges. 



Wien., p. 17. 



1883. Pachygnatha brevis, KEYSERLING . . . Ibid., v., p. 658. 



1884. Pachygnatha brevis, EMERTON . . . . N. E. Ep., p. 366, xxxiv., 21 ; xl., 8-10. 

 1889. Pachygnatha brevis, MARX Catalogue, p. 553. 



FEMALE: Total length, 5.5 mm.; cephalothorax, 2.5 mm. long, 1.5 mm. wide; abdo- 

 men, 3.5 mm. long, 2.5 mm. wide ; mandible, 1.3 mm. long. 



CEPHALOTHORAX : Glossy, with scant pubescence, the skin punctured ; a dark band of 

 brown along the margin, a median ribbon of light color extending from the forehead to 

 the base of the corselet, on either side of which is a wide band of yellow ; head well 

 elevated, quadrate, somewhat depressed in the middle of the vertex, with a lumpy appear- 

 ance on either side ; corselet grooves and cephalic suture distinct. Sternum almost an 

 equilateral triangle, elevated in the middle, and punctured. Labium blackish ; maxillae 

 glossy brown. 



EYES : Ocular quad (9a) almost square, but slightly wider behind ; eyes not greatly 

 differing in size. MF slightly larger ; side eyes propinquate, smaller than the middle 

 group, of about equal size, separated from MF by a space about equal to the area of the 

 latter, or one and a half to two times the intervening space. Front eye row slightly 

 recurved, rear row procurved. The space between SR arid MR is wider than that between 

 SF and MF, the arrangement of the eyes resembling Epeira. Clypeus height about twice 

 area MF; on one side a ridgedlike elevation extending from the margin to the midfront 

 eyes. 



LEGS : Uniform glossy yellow, with slight dark annuli at the tips of the joints ; palps 

 uniform yellow ; mandibles with four large teeth on the exterior furrow ; long, soft bristles 

 on the apex ; color glossy yellow ; fang dark brown, and slightly waved upon the under 

 surface. 



ABDOMEN : Ovate, dorsum evenly arched ; skin yellowish brown, covered with bright 

 yellow reticulations ; dorsal folium wide, with three marginal indentations ; color yellowish 



1 Count Keyserling originally described the species under this name of Koch's, but a year later pro- 

 posed the name " brevis." 



