1888.] NATURAL SCIENCES OF PHILADELPHIA. 199 



num presents somewhat the appearance of the thnmb of a human 

 hand chisped over the closed fingers ; the thumb representing the 

 posterior flap and the knuckles the folds and rugosities of the thick 

 anterior one. 

 Epeira parvula. Var. conclilea. 



5. There are few spiders that present such striking variation in 

 markings upon the dorsum of the abdomen as Epeira parvula. It 

 is a curious problem, which remains yet to be solved, what causes 

 this variety. It is probably due in some degree to those changes 

 which in certain species are evidently effected by the various moult- 

 ings which spiders undergo. But that this cannot be the sole cause 

 is shown by the fact thut the varied markings appear even among 

 mature specimens, particularly of the females. In a quite large 

 collection received from Wisconsin, through Prof. Peckham, and 

 from California through Mrs. Rosa Smith Eigenmann, I observed a 

 number of individuals upon whom a further and even more striking 

 change was manifest. 



The abdomen of Epeira parvula is triangular shaped upon the 

 dorsum, and the apical part, instead of rounding into an oval, ends 

 perpendicularly ; that is to say, is a straight wall from the spinnerets 

 to the top. In the variety alluded to, which I have named Epeira 

 coiichlea, the terminal part of the dorsum of the abdomen assumes 

 the shape of a caudal process, resembling Uiat which is characteristic 

 of the tailed spider, Cyclosa caudata. (See Fig. 6, a.) 

 This peculiarity I have traced in about a dozen spe- 

 cies, and in some much more decidedly than in others. 

 In other respects the specimens appear to be nearly 

 identical with Epeira parvula. The epigynum is in 

 form the same, although larger, the finger being very broad at the 

 base, and rapidly terminating in a point that is slightly curled. In 

 front of the base is a tri-lobed black corneous flap. (Fig. 

 6,e.) 



The body length is about 7 mm. The maxillae are 

 Fig. 6, e. broader or as broad as long and subtriangular at the tip. 

 Habitat, AVisconsin, California. 



