DESCRIPTION OF GENERA AND SPECIES. 223 



a large species; are well clothed with spines, bristles, and hairs, the spines, particularly, 

 grouped underneath the femora and tibia in longitudinal rows, and are long, strong, brown- 

 ish yellow. Mandibles brown; slightly tapering at the fangs, projecting at the base; palps 

 light yellow, the digital joint well armed with spines and bristles. 



ABDOMEN: Almost as wide as long in the specimen in hand, which appears to be a 

 gravid female. In shape a rounded oval, narrowing but little at the base, where it over- 

 hangs the cephalothorax, and somewhat more at the apex, which well overhangs the spin- 

 nerets. The dorsum beautifully reticulated, the base and front a bright yellow, which 

 extends along the sides, deepening into yellowish brown towards the apex ; dorsal field 

 silvery white, with flecks of yellow. The apical half is traversed by lateral bands of dark 

 or blackish brown, extending in semicircles around the sides to the venter; also by longitu- 

 dinal lines of the same color, one median, with side branches, more or less curved, which 

 cross the lateral bands above described, passing to the apex. The venter has a blackish 

 brown, wide band, girdled on either side by an interrupted ribbon of yellowish white, 

 which encompasses the brown spinnerets at the base, at which point it is broken into spots. 

 Within this ribbon, and symmetrically arranged upon the central band, are four yellowish 

 spots, the anterior ones closer together than the posterior. In the epigynum (Plate XIV., 

 Fig. la) the scapus is without a free end, which, like the curved clasp in a padlock, bends 

 over from the posterior to the anterior side of the atriolum, thus dividing the portulse or 

 seminal chambers. In this respect it resembles the epigynum of A. argyraspis and A. 

 argentata. 



DISTRIBUTION : In the United States, Fort Yuma, Arizona. (Marx Collection.) Orig- 

 inally described by Dr. Thorell from a specimen collected on the voyage of the frigate 

 " Eugenies." 



No. 75. Argiope Marxii, new species. Plate I, Fig. 5. 



1890. Epeira americana MARX, in Hit. 



FEMALE: Total length, 17 mm.; cephaiothorax, 6 mm. long by 4.5 mm. wide; abdo- 

 men, 12 mm. long by 7 mm. wide. This fine large spider has a strong resemblance to A. 

 argyraspis, from which, however, it may be at once distinguished by the oval contour of 

 the abdomen and the absence of the strong annular markings on the legs. 



CEPHALOTHORAX : A rounded oval, widest towards the base, which is truncated and 

 shelving, thin, flat upon the summit, the fosse a deep rounded pit; cephalic suture deep; 

 corselet grooves sufficiently distinct; color brownish yellow, with darker bands along the 

 grooves and on the median of the caput, covered scantily with silvery gray hairs. The 

 sternum is shield shaped, somewhat longer than wide, indented at the edges; with sternal 

 cones; rounded in the centre, the color blackish brown and yellow. Labium wide at the 

 base, subtriangular at the tip; maxillae rounded, nearly as wide as long, and, like the 

 labium, brown, with yellowish tips, and covered, like the sternum, with numerous black 

 bristles. 



EYES: Ocular quad on a prominence, most decided in front; rear slightly wider than 

 front, sides decidedly longer; MF separated by about one diameter, MR by 1.5 to 2 

 diameters, smaller than MF; side eyes on tubercles, slightly separated, about equal in size; 

 MF removed from SF by about 1.3 their area, and from the margin of the clypeus by 

 about 1.5 to 2 diameters; front row recurved, rear row slightly procurved. 



LKGM: Long, stout, freely armored with hair and black bristles, the latter arranged in 

 tliirk rows along the upper surface; spines numerous, long, blackish, arranged in rows 

 underneath the joints; beneath the femora especially are three rows of long spines, with 

 elevated bases, of which the largest is directly in the middle of the joint. The other 

 femora are similarly, but less abundantly, provided, and there are spines also beneath the 

 tibia. The color is yellow (in the alcoholic specimen), with no indication of annuli, but 

 darker bands upon the femora beneath; the palps are of like color and armature; the 



