EPHEMERIN^E. 539 



Genus 2. POTAMANTHUS. 



Oculi maris duplices. Pedes bene determinati. Setae caudales 

 tres. Alae reticulatae, quatuor, venis transversis plurimis. Larva 

 non depressa, repens, nun subiens, cauda simplici. 



Potamanthus, Pictet, Hist. Nat. Neur. Eph. 197. 

 Ephemera, p., Steph. 

 Ephemerae trisetae, p., Zett. 

 Ephemeridae, p., Newman. 



Each of the ordinary eyes of the male surmounted by a large 

 reticulated eye, whose superior border rests against the front eye : 

 wings four, with numerous transverse veins, which are delicate, and 

 often invisible to the unaided eye : hind-wings smaller than those 

 of the three preceding genera, but with a complete neuration : ab- 

 dominal tentaculae of middle size ; internal appendages conical, of 

 moderate size : three tail-bristles of equal length. 



1. POTAMANTHDS FERRERI. 



Corpus Icete flavum ; seta caudales non annulatce ; al& distinctis- 

 sime reticulate, venis transversis pallidis. 



Potamanthus Ferreri, Pictet, Hist. Nat. Neur. Eph. 203, pi. 25, f. 1 . 

 Switzerland. 



2. POTAMANTHUS LUTE us. 



Corpus Icete flavum ; setae caudales annulatce ; alee distinctissime re- 

 ticulatce, venis transversis fuscescentibus. 



Ephemera lutea, Linn. Syst. Nat. Ed. 12, ii. 906, 2. Geoffr. 

 Hist. Ins. ii. 239, 2. Schceff. Icon. Ins. Ratisb. 42, f. 7 ? 

 Sulz. Abg. Gesch. 171, pi. 24, f. 6. Fabr. Ent. Syst. ii. 

 68, 2. Gmel. Ed. Syst. Nat. i. 2628, 2. Schrank, Ins. 

 Austr. 603 ; Faun. Boic. 1939. De Vill. Linn. Ent. iii. 17, 2. 

 Rossi, Faun. Etrusc. ii. 673. Oliv. Enc. Meth. vi. 417, 2. 

 Walck. Ent. Par. ii. 8, 2. Latr. Hist. Nat. Ins. xiii. 95, 2. 



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