60 Rey. A. H. Haton’s Monograph 
laceo-fusco. Pedes antici nigricantes. Abdomen fulvo- 
griseum, striga supra fusca in medio, postice quam antice 
latiori. Sete albicantes. (Pict.) 
Long. corp. @ 11, exp. al. 38 mm. 
Hab.—Brazil. (Burm.) 
Genus PoLymirarcys. 
(Ala antica, Pl. I. fig. 5.) 
Ephemera, p., Ol. 1791; Palingenia, p., Burm. 1839 ; 
Polymitarcys, Ktn. 1868. 
Imago. Oculi integri; ale quatuor; pedes debillimi, 
femoribus brevissimis. 6 Forcipis pes vel quadri- vel 
tri-articulatus, secundo articulorum longissimo. Setarum 
media est brevissima. Ungues antici tenues, obtusi et 
impares. ? caret ovivalvula, et setas tres equales habet. 
Polymitarcys virgo. 
(Genitalia maris, Pl. III. fig. 15, 15 a b.) 
Bphemera virgo, 01.1791. H. marocana ?, Fab. 1793. EH. 
lutea, Pz. 1804. Palingenia horaria, Burm. 1839. H. albi- 
pennis, Voigt, 1840. Palin. virgo, Pict. 1843-5. 
Subimago, v. s. s. Imagine pallidior, setis pubes- 
centibus. 
Imago, v.s.s. 6. ‘‘Oculi atri; caput infra in fronte 
atrum.’’ Prothorax testaceus; meso- et meta-thoraces 
lutescentes. Ale albz; nervi transversales apicales 
areee marginalis simplices et subrecti. ‘‘ Pedes albi- 
cantes, femoribus anticis infra cum tibiis suis fere in toto 
atris.” Abdomen cretaceum, griseo-nebulosum apicem 
versus. Setze et forfex albee. 
Long. corp. 6 2? 16-17; exp.al. 9 33; set. ¢ im. 
23, subim. 18; set. 2? 1m. 13 mm. 
Hab.—Central Europe, in large rivers (e.g., Paris, 
Cologne, and Mannheim); Madrid. 
The subimagines rise from the rivers in immense 
numbers late in the evening, in August, and soon moult. 
The species from Morocco is possibly distinct from P. 
virgo. 
= ‘ ee 
