296 EEV. A. E. EATON ON EECENT EPHEMEEEDJi: OE MAYFLIES. 



EPHEMERID^ OF UNCERTAIN GENERA. 



The generic names here attributed to sjDecics placed in this category, when not of 

 very recent origin, are used in a lax and unrestricted sense, such as was accorded to them 

 hy Pictet (1843-5) or by myself in the year 1871. 



AMERICAN SPECIES OP UNCERTAIN GENERA. 

 PoTAMANTHTJS VoGLERi, Weyenbergh. 



Cloe (?) Voyleri, Weyenbergli, Tijdschr. v. Eut. xxvi. 1882-3, p. 171, pi. x. 5 (1883) [wings]. 



Imago [living), <2 . — Thorax jet-black ; abdomen black ; setae 3, greyish, with black 

 joinings ; legs somewhat pearl-grey, but darker. Wings vitreous, with black neuration, 

 excepting that the fore wings from the costa to the radius are dark-tinted. [In the 

 figure the proximal half of the marginal area is colourless.] Hind wing very small, 

 traversed liy a single longitudinal median nervure, which does not extend quite to the 

 margin. 



$ . — Abdomen of lighter colour than that of the male. Length of body 3"5, setae 14- 

 15 nam. 



Hah. ki Pasco Sobremonte, Cordova, Argentine Republic, flying in the sunshine at 

 about 8 A.M., on the 20th of Api'il. 



From the figure of the fore A\ing and items detailed in the original description, it is 

 evident that tiiis species represents a genus of the Fifth Section, or Leptophlehia-iy^^. 

 What is stated of the hind wing should, perhaps, be received with caution, because, from 

 inspection of the figures, it appears that Prof. Weyenbergh was not accustomed to flatten 

 out the wings he delineated. 



PoTAMANTUUS SiEWERTii, Weyenbergh. 



Cloe Siewertii, Weyeubergh, Tijdschr. Ent. xxvi. 1882-3, p. 170 (1883). 



Imago (living). — Upper portion of oculi dark red ; thorax sepia-brown ; abdomen dark 

 grey, darker at the joinings ; setse 3, pearl-grey, with darker joinings. Femora [sprieten] 

 blackish ; the remainder of the legs [pooten] light grey. Wings dull, spotless. Hind 

 wings very small. Length of body 3, sette 9 mm. 



Ilab. Cordova, Argentine Republic ; sparingly in November. 



POTAMANTHUSi?) INANIS, Pictet. 



PotamanthuslW inanis, Pict., Hist. Nat. Nevropt. ii. Ephem. 232, pi. xxiv. 4 (1842-5); Walk., List of 

 Ncuropt. lus. in Brit. Mus. 517 (1853) ; Etn., Trans. Ent. Soc. London (1871) 91 [nee E. inanis, Gmel. 



1790]. 



Imago {dried), d . — Thorax polished bright brown. Abdomen whitish for the most part, 

 but with the tip brown, and with a large brown dot on each side of every whitish 

 segment. Setae greyish, dotted with black. Legs brown. Wings vitreous, shghtly 

 greyish, rather darker along the costa, and tinged faintly with yellowish at the base; 



