238 AMERICAN SPIDEKS AND THEIR SPINNINGWORK. 



No. 90. Zilla atrica C. Koch. Plate XVIII, Figs. 7, 8. 



1802. Aranea calophylla, Walckenaer . Faune Par., ii., p. 200. (In part.) 



1805. Epeira calophylla, Walckenaer . Tabl. d. Aran., p. 62. (In part.) 



1834. Zygia calophylla, Koch, C. . . . Herr.-Schaeff, Deutschl. Ins., 123, 17. (In part.) 



1844. Eachana atnca, Koch, G Die Arachn., xii., p. 103, pi. 419, Figs. 1030, 1031. 



1851. Epeira alrica, Westring .... Forteckning, etc., p. 35 



1856. Zilla airica, Thorell Recensio Critica, p. 107. 



1861. Zilla alrica, Westring Aranea; Sveeicse, p. 69. 



1864. Epeira calophylla, Blackwall . . Sp. G. B. & I., ii., p. 338, xxv., 245. 



1866. Zygia alrica, Menge Preuss. Spinn., i., p. 78, pi. 12, tab. 20. 



1867. Zygia calophylla, Ohlbrt .... Aran. d. Prov. Preuss., p. 30. 



1889. Zilla atrica, McCook Amer. Spiders and their Spinningwork. 



1889. Zilla atrica, Marx Catalogue, p. 550. 



Female: Total length, 8 mm.; abdomen, 5.5 mm. long, 3.5 mm. wide across the base; 

 cephalothorax, 4 mm. long, 2.5 mm. wide; the face, 1.5 mm. The general colors of the fore 

 part are yellowish .brown, and of the abdomen yellow, white, and blackish. 



Cephalothorax : A long oval ; black on the summit ; the sides high ; fosse a longitu- 

 dinal slit; corselet grooves not distinct; cephalic suture distinct; color brownish yellow, 

 lighter on top, with a patch blackish at the caput base, and a dark band passing thence to 

 the eye space; slightly pubescent, especially around the caput base; skin glossy along lower 

 margin of corselet ; a row of bristles curved along the front. Sternum longer than wide, 

 shield shaped; glossy at the margin, with a broad yellow median band; sternal cones dis- 

 tinct, indented on the edges, raised in the centre. Labium triangular; maxillfe as broad as 

 long ; subtriangular at tip ; light brown, shading to yellow at tij). 



Eyes: Ocular quad slightly wider behind than in front, and the side somewhat longer. 

 Eyes about equal in size. MF separated by about one diameter; MR by about 1.5 diameter. 

 Side eyes on tubercles; contingent; about equal in size, and not greatly different in size 

 from MR. SR removed from MR by a space but little greater than the distance between 

 MR. The space between SR and MR at least twice the distance between the latter. The 

 front eye row recurved ; the rear row longer, and procurved. The clypeus is about the 

 height of one diameter MF. 



Legs: 1, 2, 4, 3; stout, particularly the femora; yellow, with dark brown annuli at tips 

 of joints, and median annuli on femora and tibia, especially underneath ; spines short, 

 black, few in number ; the joints not heavily but sufficiently clothed with yellow hair and 

 bristles. IMandibles uniform brown, slightly pubescent, extending almost directly from the 

 face, and sharply bent downward ; conical ; quite thick at the apex ; parallel. 



Abdomen : Oval, but slightly diminishing toward the apex, where it is nearly as thick 

 as at tlie base. The folium is a broad, oval figure, with undulating margins of black, 

 mottled with yellow, there being about five prominent scallops thereto ; it narrows to the 

 apex ; the central pai't is yellow, with branching longitudinal lines from the median point 

 backward. The dorsum is reticulated, the sides well covered with liairs, the whole having 

 a slightly glistening appearance in life. The venter has an irregular rectangular patch of 

 brownish yellow, well covered with yellowish hairs, and a margin reticulated on either side. 

 The epigynum (Fig. 7a) is dark brown, glossy in color, lacking the prominent scapus char- 

 acteristic of most species of Epeira. The figure on the plate is not a very good representa- 

 tion thereof. 



The Male: Figs. 8, 8a. Is smaller than the female, being 6 mm. long, and resembles 

 it in general color and markings, although the legs are less decidedly annulated. Tliese 

 members are long, provided with comparativeiy few spines, with no special clasinng spines 

 upon tibia-II; color uniform yellowish brown. The palps (Fig. 8a) are long and strong, and 

 thus are an admirable substitute for the tibial clasping spurs. 



Zilla atrica is distinguished from Z. x-notata, which it strongly resembles, (1) by the 

 reddish brown color of the mandibles; (2) it does not have, in the living species, the 

 shining black, and, after death, the blackish, color of the latter; (3) the black bases of tlie 



