DESCRIPTION OF GENERA AND SPECIES. 269 



Male: About the size of the female, which it closely resembles in form, color, and 

 markings. The eyes (2a) are arranged substantially as in the female, though the rear eyes 

 appear to be relatively somewhat larger. The front row is almost straight. The radial 

 joint of the palp (2b) is short, scarcely equaling in length the cubital. The digital joint is 

 rounded at the base, and very long. 



Distribution: District of Columbia (Marx Collection). Keyserling's original description 

 was made from a specimen found by Dr. Marx in Harrisburg, Pennsylvania. The species 

 probably inhabits the Atlantic and Middle States. 



No. 115. Pachygnatha xanthostoma C. Koch. Plate XXVI, Figs. 7, 8. 



1845. Pachygnatha xanthostoma, C. Koch . . Die Arach., xii., p. 148, Figs. 1068, 1069. 

 1883. Pachygnatha xanthostoma, K-EYSEKLISG, N. Spinn. Amer., v., p. 659, pi. 21, Fig. 9. 

 1889. Pachygnatha xanthostoma, Maks . . . Catalogue, p. 553. 



Female : Total length, 4.5 mm. ; cephalothorax, 1.5 mm. long ; abdomen, 3 mm. long, 

 1.8 mm. wide. 



Cephalothorax : Cordate, rounded at the edges, well elevated in the centre ; corselet 

 grooves distinct ; cephalic suture well marked ; head elevated about corselet level, arched 

 upon the summit to the eye space ; color brown, with lighter streakings upon the sides. 

 Sternum widest near the base, pointed like an arrow head towards the apex ; raised in the 

 middle. Color dark brown, with lighter median shade ; covered with short, rather stifl' 

 hairs. Labium subtriangular, wide at the base, more than half the height of the maxillae, 

 blackish brown color ; maxilhe elongate, longer than wide, convex externally, pointed 

 toward one another, the tips roundly truncate. Color yellowish brown. 



Eyis : Ocular quad (7a) slightly elevated, the length somewhat greater than the rear 

 width ; wider behind than in front. MF somewhat smaller than MR, separated by 1.5 

 diameter; MR by 1.7 to 2 diameters. Side eyes upon low tubercles, nearly contingent; SF 

 larger than SR. Space between SF and MF about equal to the area of the latter, or 1.5 to 

 2 times the interspace of MF. The distance between SF and SR is slightly greater than 

 the interspace of SR. Front eye row recurved, rear row slightly recurved, and somewhat 

 longer ; the clypeus height about equals area MF. 



Legs: 1, 2, 4, 3; color uniform yellow to yellowish brown, without annuli; palps 

 colored and armed as the legs ; mandibles brown, widest at the tips, which are cut with 

 an incline inwardly toward one another (7a); fang not reaching the maxillse ; teeth 3-4, 

 nearly uniform in size- 



Abdomen: Oval; the dorsum evenly arched. The dorsal folium with three to four 

 indentations; dark brown to yellow in color, outlined by black, and with a median blackish 

 band. The sides have an interrupted band of yellow, beautifully reticulated, followed lower 

 down by a dark brown belt, which touches the venter, which is a blackish band extending 

 between spinnerets and epigynum (7b), which is a simple atriolum. 



Male: (Fig. 8.) From 3 to 3.5 mm. long,* closely resembling the female in color, 

 form, and markings. The radial joint of palp (8b) is scarcely longer than the cubital, and 

 is less than half the length of the digital. A slight spur marks the dorsal apex of the 

 mandibles; the teeth number 3-4, and are of nearly uniform size; the fang has no decided 

 angular projection on the inferior surface. 



Distribution : The examples from which the above description was made were found 

 in the neighborhood of Philadeliihia. Dr. Marx has collected the species in Pennsylvania 

 and in the District of Columbia. It is probably common throughout the Eastern and 

 Middle United States. Mr. C. L. Koch described both male and female from specimens 

 collected in Pennsylvania. 



* The male of Koch's original description is, on the contrary, somewhat larger than the female, 

 instead of smaller, as here. 



