192 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



hairs. Sternum cordate, one-half longer than broad, with sternal cones, color yellow, 

 numerous bristlelike hairs; labium dark brown at the base; maxillie gibbous, longer than 

 broad, liiuntly triangular at the tips, which are inclined inward. 



Eyes: Ocular quad elevated; length somewhat greater than width, rear slightly wider 

 than front; MF separated by about one diameter; MR about 1.5 their diameter; side eyes 

 on black tubercles; barely contingent; SF somewhat larger than SR ; SF removed from MF 

 by about 2.5 the area of the latter, or at least tive or six times the intervening space of 

 same; SR removed from MR by a slightly greater distance than separates SF and BIF; 

 clypeus height about two diameters IMF, the base of the rounded eminence coming close to 

 the margin ; the front row is scarcely curved, the eyes aligned ; the rear row is a little 

 longer and slightly procurved ; the forehead is high and well rounded. 



Legs: 1, 4-2, 3; rather short, but drawn too short and pomted in the figure; stout; 

 color dull (greenish) yellow, except the feet, which are brown; well provided with 

 pubescence and whitish yellow bristles, somewhat sparingly with rather short yellowish 

 brown spines; palps armed and colored as the legs; mandibles strong, conical, yellow, with 

 slight brown at the tips. 



Abdomen : A long triangular ovate, widest at the summit of the base ; tlie front raised 

 high above the cephalothorax ; the dorsum not arched, but rather flat or curved inward to 

 the apex, which terminates in a rounded cone or caudal part, although Cambridge describes 

 this part as "not in a caudal form." Strong conical shoulder humps, which terminate in 

 sharp brown points, mark the base ; the folium is not distinct ; the general field is yellow, 

 reticulated, with brownish margins, from which issue longitudinal lines to the apex, which 

 is touched with blackish brown, and covered with a tuft of yellowish hairs; the spinnerets 

 are placed far underneath the projecting apex of the abdomen, brown in color, surrounded 

 by a base of yellowish spots ; the venter is brown, witli marginal ribbons of yellow merg- 

 ing into the sides, which are brown, with yellowish lateral patches ; the epigynum presents 

 a subtriangular cup shaped scapus, very wide at the base, rounded at the top, brown and 

 chitinous; the basal part thereof is an irregular quadrilateral, somewhat wrinkled; smooth 

 and hollowe<l on the lower part, like the scapus. Cambridge's drawings of this seem very 

 defective, probably from an immature species. 



Distribution: Biscayne Bay; two specimens, female. (!Marx Collection.) Cambridge 

 describes it from Panama. The-- species is thus probably distributed along the coasts of 

 Central and subtropical North America. 



Gexus MARXIA, new. 



I have thought it necessary to make a new genus to receive the species originallj' 

 described by Walckenaer as Plectana stellata. Subsequent writers have relegated this 

 species to Epeira, on the grounds of the strong likeness in the mouth parts, the general 

 grouping of the eyes, and form of the legs. The peculiar tuberculated condition of the 

 abdomen has not been regarded by these authors as of general value. To me it seems 

 unreasonable that an organ of such prominence, which contains the vital organs, and 

 especially the spinning apparatus, by whose functions the animal is most sharply differen- 

 tiated from members of its class, and, indeed, all other animals, should count for nothing 

 in classification. It has been urged that the abdomen, by its softer covering, is more 

 plastic, and therefore presumably more liable to changes, through environment and other 

 influences, than the harder cephalothorax. Yet I have not found that, in point of fact, 

 the abdomen is less persistent in its peculiar forms, as characteristic of various species, 

 than other parts. 



I have therefore considere<l that a peculiaritj' so striking as that shown in the tuber- 

 culated margins of the dorsal field, if not sufficient ground in itself for separating these 

 specimens from Epeira, at least should be considered as one distinctive feature. In addi- 

 tion, however, Marxia is well separated from Epeira by the form of the cephalothorax, 

 which is strongly elevated at the caput above the corselet. In Epeira, on the contrary, the 

 head is on a level with the crest of the corselet, or more frequently depressed tlierefrom. 



