196 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



No. 53. Marxia mcesta (Keyserling). Plate XII, Figs, ii, iia-c. 



1889. Epeira maesta, Marx in Kit. . . . Catalogue, p. 546. 



1892. Epeira mosta, Keyserling .... Spinn. Amerk., Epeir., p. 108, Fig. 80. 



Female: Total length, 11 mm.; cephalothorax, 5 mm. long, 3..5 mm. wide, 2.5 mm. at 

 the face; abdomen, 9 mm. long, 8 mm. wide across the base, narrowing to 1.5 mm. at 

 the face. 



Cephalothorax : Oval, well rounded at the sides, trimcate behind, where it is over- 

 hung liy the abdomen; coreelet grooves sufficiently distinct; cephalic suture well marked, 

 as is the median fosse. Color dark brown, with lighter ban<l of yellow along the corselet 

 margin ; head colored as corselet, and rises from the fo.sse at a slight inclination ; is arched 

 on the posterior and narrower half, and about midway has two knobs, such as appear in 

 other species of the genus; thence the fore part of the caput is depressed to the central 

 eye space, which turns up mto a strong prominence, giving from the side view a snouted 

 appearance to the face. In front the face is wide, but the eye space is distinctly sepai-ated 

 from the knobby summit of the cajnit liy the depression above alluded to. Sternum shield 

 shape, well rounded at the sides, subtriangular at the apex, glossy, dark brown, or blackish, 

 elevated in the centre and flattened, with sternal cones, sparsely covered with grayish 

 white hairs, which are thickest on the anterior part; skin hard and glossy. Labium widest 

 at the base, where the color is dark brown, the tip obtusely triangular; maxillie colored 

 like the lip, rounded, at least as wide as long. 



Eyes: Ocular quad on a high prominence, most elevated behind; the rear slightly 

 narrower than the front, which about equals the sides; MF separated by nearly two 

 diameters, about equal to MR, which are separated by a little gi-eater space. Side eyes on 

 tubercles much less prominent relatively than the median one ; separated by a diameter of 

 SR, which is smaller than SF. The space between SF and IMF equals about twice the area 

 of MF, or 2.3 times the distance between IMF. Height of clypeus equals alignment of MF. 

 Both rows viewed from the front are procuryed, the hind row more so, and is much longer 

 on account of SR being placed so far to the side; the margin of the dypeus has yellowish 

 gray bristles. 



Legs: 1, 2, 4, 3 ; stout; in color dark brown, provided with grayish yellow bristles and 

 spines. The palps are colored and armed as the legs. 



Abdomen : Subtriangular in form, widest at the base, where it is rounded to the front, 

 and far overhangs the cephalothorax. The dorsum is somewhat flattened, and the abdomen 

 is almost as thick at the apex as in front. Two slioulder tuliercles mark the base well back 

 of the anterior middle point, leaving thus the fore part of the abdomen as a wide sub- 

 triangular space sloping toward the front, while the remainder of the dorsum slopes some- 

 what, though but little, toward the rear. The apex is marked by a prominent rounded 

 tubercle, resembling those upon the shoulders, but smaller; on either side of this is a 

 similar smaller tubercle, and beneath it on the apical wall of the abdomen are two others 

 in a row, of similar character, but somewhat flattened. The color is yellow, much broken 

 by irregular and lateral black lines upon the sides. Between the shoulder tubercles and 

 the apical ones extends a folium of dark or darkish brown, mottled with yellow reticula- 

 tions, dentated upon the edges and narrowing toward the apex ; an interrupted yellowish 

 band marks the middle of the dorsal tield. The basal front has the same black and yellow 

 reticulations that mark the sides. The venter has a broad black band, with lateral mark- 

 ings of yellow at the front; the spinnerets are black, with yellowish spots at the base; the 

 epigynum (Figs, lib, lie) has a well arched atriolum, and a scapus whose base is wide and 

 spooned, giving the edges a horseshoe shape; from its central point issues a long lanceo- 

 lated tip. 



Distribution: Pike's Peak, Colorado; New Mexico. (Marx Collection.) Only the 

 female of this species is known. The localities in which it has been found would indicate 

 a geographical distribution throughout the Southwestern States and Territories, and prob- 

 ably the Pacific Coast. 



