l>i;s<:ulI>TION OP GKNKRA AND SPECIES. 1 7"> 



THE ANGULATA GROUP OF EPEIRA. 



One meets a series of small Epei'roids, mostly of the Angulata group, which are char- 

 acterized by several common features, and some of which are difficult to distinguish one 

 from another. They all possess a peculiarly shaped epigynum, which is generally char- 

 acterized by having a long convoluted scapus of cretaceous or whitish yellow color, of 

 about equal breadth throughout the stalk, and widening at the tips into a broad spoon or 

 ladlelike oval. This peculiarity at once strikes the observer, and compels him to place 

 the species together in one group. Moreover, he observes that they are all small, being 

 about 5 mm. in length, a little more or less. ;These species are furthermore found to 

 resemble one another in the general shape of the face and arrangement of the eyes; 

 an agreement which extends to the form of the cephalothorax, which is somewhat oval, 

 rounded at the margins of the corselet, pitched high in the middle, and sharply slopes 

 before and behind. The resemblance is further seen in the strong, well arched shape of 

 the caput, rather squarish in its general contour, and wide at the face. 



Looking at the abdomen, the series is at once seen to be divided into two sections, of 

 which one, like Epeira juniperi and E. linteata, has an ovate abdomen, smooth upon the 

 surface, that is, without shoulder humps. Comparing the above two species, one remarks a 

 difference in the shape of the atriolum, which in E. juniperi is divided in the posterior 

 partj leaving the portulse rather distinct, and having curved, pointed, or ram's horn proc- 

 esses issuing from the inner side of the bases. E. linteata has an atriolum that is more or 

 less continuous, being somewhat bowl shaped, from the middle of which the scapus arises, 

 and this is shorter than E. juniperi's. The abdomen of Linteata is also more triangular in 

 shape than that of Juniperi. 



Passing to the other, or Angulata section, the differences are not so marked, and the 

 species are often difficult to determine. The species which I take to be typical of the well 

 known Hentzian Epeira scutulata, which must now yield to the prior name of Walckenaer, 

 E. miniata, is distinguished by two leaflike appendages (Plate VIII., Fig. 8c), which arise 

 from the base of the atriolum near the issue of the scapus, and are held aloft upon a short 

 stalk, which, like the leaflike process, is black. E. Mayo lias the same characteristic 

 scapus (Plate VIII., Fig. lla), though perhaps a little more rounded or ladlelike; but the 

 atriolum is without the leaf shaped appendages, and sends out two broad curved sides, 

 which in some specimens unite underneath the tip of the scapus, seeming to form a con- 

 tinuous bowl. In other specimens these are seen really to be separate, and to form simply 

 flanking walls of the portulse. In E. Bonsallfe (lOb), on the contrary, the epigynum 

 strongly resembles that of E. juniperi, having the ram's horn appendages to the inner 

 baaes of the portuhc. The tip of the scapus is not quite so circular as that of Mayo, but 

 this may be an individual characteristic. The abdomen of E. Bonsallse is at once distinct 

 from that of Juniperi, by being subtriangular, having short shoulder humps, and possess- 

 ing V-shaped rows of brownish spots approximating at the apex. E. Paciflca 1 differs from 

 the other species of the section to which it is most closely allied, by the strong character 

 of the dorsal folium ; by the deeper brown bands upon the legs, and the median annul! ; 

 by the generally stronger and darker colors of the whole animal ; and, moreover, by the 

 form of the epigynum, the scapus of which is much convoluted, issuing from the base of 

 a bowl shaped atriolum, which is continuous both in front and behind, and not dividing 

 underneath the tip of the scapus, as is the case in Mayo, from which species it also differs 

 by the general markings and color. 



It is possible that future students, who may be favored with more numerous specimens 

 from which to judge, may find that these characteristics, some of them at least, are more 

 individual than specific ; or, that instead of giving good grounds for specific distinction, 

 may simply establish varietal forms of one common species, of which E. miniata may be 

 held as the principal form. I have presented these differences as they appear to me, in 

 the hope to simplify and economize the labors of naturalists, who are sure to find, as I 

 have found, much labor and perplexity in discovering good characteristics by which to 

 distinguish this perplexing group. 



