Hemming (1967) stated:-
The name Potamanaxas was introduced by Lindsay to replace the name Potamanax Watson, 1893, which is invalid under the Law of Homonymy.
Cowan (1970: 19) stated:-
"POTAMANAXAS flavofasciata - Equat. Led. Buckley (4) : 76
HEWITSON, 1869-77; Equat./Ecuad. Lep. Buckley/Bolivia.
Among his many writings, Hewitson published a series of five short papers under two titles in 1869-1877, Meanwhile in 1870 he wrote a short article in a periodical, of which repaginated reprints were circulated, and then in 1874 he issued another separate short publication. All these bore related titles and some confusion has resulted. The following notes may help.
Equatorial Lepidoptera collected by Mr. Buckley. (1) - (5).
Remarks on and descriptions of new species of Butterflies collected by Mr. Buckley in Ecuador. (1)-(5).
These two titles are synonymous for the same work. No title-page as such was issued. The short title appears on the wrappers of all five parts. The longer title was used at the head of part 1, page 1, but nowhere else. The latter is misleading. It is considered that the latter (as cited by Hemming, 1967 : 461 under Zabirnia) should be disregarded and the former used (cited : 124 under Composteria and passim). The reference to Hewitson under Yanguna should also be to this. The work may be collated as;
Equat. Lep. Buckley (1) (2 Dec. 1869): pp. 1-16 (species nos. 1-26)
Equat. Lep. Buckley (2) (15 Dec. 1869) : 17-32 (nos. 27-56)
Equat. Lep. Buckley (3) (30 Dec. 1869) : 33-48 (nos. 57-87)
Equat. Lep. Buckley (4) (10 Mar. 1870) : 49-79,  (nos. 88-145)
Equat. Lep. Buckley (4) (10 Mar. 1870) : [i], ii (Preface), [iii, iv] (Index)
Equat. Lep. Buckley (5) (11 Apr. 1877) : 81-96 (nos. 1-30) (no index).
Hewitson explained in his preface that Buckley had returned from a year's tour of Ecuador, where he had been assisted by Manuel Villagomes. Later, Buckley toured Bolivia, and his specimens were written up in part (5), as noted in a short opening paragraph. Thus the longer title restricted to Ecuador is unsuitable, and the late appearance of part (5) is accounted for.
Meanwhile Villagomes independently sent from Ecuador a small collection of his own which Hewitson described under the title "Descriptions of 22 new Species of Equatorial Lepidoptera" in Trans. ent. Soc. Lond. 1870 (2) : 153-163. No new genera were introduced here, and none of the species has since been used to typify a genus. It is the title of this paper which wrongly appears under Yanguna; the page 69 in question belonging to part (4) of the former work.
Finally, Buckley produced another collection which Hewitson for some reason made the subject for yet another separate publication; Descriptions of new Species of Butterflies collected by Mr. Buckley in Bolivia, 22 pp., London, 1874. This introduced two new genera, Hermathena and Xynias and described species nos. 1-52 (omitting 5-10, 23-27 which he figured in his Exot. Butt. instead), of which three have since been made type-species. Hemming cites this work five times; on three occasions (cf. Xynias) he gives Descr. new Spec. Butts. Buckley Bolivia, which is ideal, but the others are less clear.
The higher classification used here follows Lamas (2008).
Learn more about Hesperiidae in Wikipedia.
See images at Butterflies of America where it is treated in the Pyrrginae: Erynnini.
Search the Biodiversity Heritage Library (BHL) for references to POTAMANAXAS and included species.
Potamanax Watson, 1893: 43 (key), 55.
Potamax ; Spitz, 1932: 872.
Potomanax ; Evans, 1953: 137.
Potomanaxas ; Evans, 1953: 15, 137.