ephemeriNjE. 539 



Genus 2. POTAMANTHUS. 



Oculi mavis duplices. Pedes bene determinati. Setae caudales 

 tres. AI33 reticulata, quatuor, venis transversis plurimis. Larva 

 non depressa, repens, nun subiens, cauda simplici. 



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

 Ephemera, p., Steph. 

 Ephemeras trisetoe, 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 tentacular of middle size ; internal appendages conical, of 

 moderate size : three tail-bristles of equal length. 



1. Potamanthus Fekeeri. 



Corpus late Jiavum ; seta caudales non annulata ; alee distinctis- 

 sime reticulata, venis transversis pallidis. 



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

 Switzerland. 



2. Potamanthus luteus. 



Corpus late Jiavum ; seta caudales annulatce ; alee distinctissbne re- 

 ticulata, venis transversis fuscesccntibus. 



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

 Hist. Ins. ii. 239, 2. Schaff. 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. Mkth. vi. 417, 2. 

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



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