The North American Species of Mimetus 



By Ralph V. Chamberlin 



In his "Araneides of the United States," Hentz describes three 

 species under the genus Mimetus : namely, interfector, tuberosus 

 and syllepsicu.-^. Of these three sijllepxirii:^ has not since been defi- 

 nitely identified, while tuberosuii is generally regarded as a synonym 

 of interfector, a disposition with which no fault can be found. In 

 1882 Emerton described a male from Connecticut under the name 

 M. ejieiroides: but the practice in recent years has been to refer all 

 individuals of the genus found in the United States to one species, 

 interfector, and, accordingly, in current catalogues epeiroides has 

 been placed in synonymy with that species. 



However, a careful study of ample material of Mimetus from 

 various parts of the country reveals that there are at least five 

 clearly distinct species that have been confused under the name 

 interfector. One species occurs on the Pacific Coast apparently 

 from Washington to southern California and eastward to Texas. 

 Two species occur in the Northeastern States, the commoner of 

 these ranging southward as far as northern Georgia. The other 

 two species are common in the Southern States ; and one of them is 

 found as far northward as Long Island, N. Y. It seems reasonably 

 certain that it was one of these two southern forms that was de- 

 scribed by Hentz as interfector. the particular one being fixed, it is 

 believed, by the figure of the palpus as indicated later in the notes 

 on the species. Tuberosus is left as a synonym of interfector; but 

 syllepsicus cannot be placed at present and is apparently different 

 from any of the five species here listed. 



The males of these five species are easily recognized by the 

 characters presented in the palpus, the armature of the ectal mar- 

 gin of the cymbium providing a convenient index. Another readily 

 observed character of diagnostic importance occurs in the ter- 

 minal portion of the bulb which in the retracted organ lies adjacent 

 to the base of the embolus and presents typically two flat or lamellar 

 lobes projecting proximad. In one species (notius) one of these 

 lamellar lobes is aborted and in another (puritamis) the second lobe 

 is itself partly divided or bilobed. 



The four species of which females are known may be sepa- 

 rated in that sex by the characters of the epigynum, which is in the 

 form of a strongly chitinized, transversely furrowed, caudally pro- 

 jecting lobe. At the caudal end of the epigynum. or near it on 

 its dorsal side, is an opening or pit and cephalad or proximad of 

 this on the dorsal side is a separately chitinized median longitudinal 

 piece or strip. The position and form of this epigynal opening or 

 pit, the size and position of caudal end of the median dorsal strip, 



