EPHEMERIN.E. 545 



Potamantbus gibbus, Pictet, Hist. Nat. Neur. Eph. 226, 9, pi. 

 31, 32. 



Switzerland. 



17. POTAMANTHUS SUBMARGINATU3. 



Rufo-piceus ; pedibus pallidioribus, gcniculis posticis nigricanti- 

 bus ; alis hyalinis, costa subochracea. 



Ephemera submarginata, Sieph. III. Brit. Ent. Mand. vi. 58, 7. 

 Potamautbus submarginatus, Pictet, Hist. Nat. Neur. Eph. 236. 



Allied to P. erythrophthalmus. 

 England. 



18. POTAMANTHUS DILUTUS. 



Pallide rufo-ferrugineus ; abdomine nigricante ; pedibus pallidis ; 

 alis hyalinis costa concolore. 



Ephemera diluta, Steph. III. Brit. Ent. Mand. vi. 58, 10. 

 Potamantbus dilutus, Pictet, Hist. Nat. Neur. Eph. 236. 



England. 



19. POTAMANTHUS HOSEUS. 



Pallide roseus,subnitidus; pedibus pallidioribus; seds luridis fusco 

 maculatis ; alis hyalinis basi summa et costa dilute roseis. 



Epbemera rosea, Steph. III. Brit. Ent. Mand. vi. 59, 13. 

 Potamanthus roseus, Pictet^ Hist. Nat. Neur. Eph. 236. 



England. 



20. Potamanthus .eneus. 



Corpus latum, breve, Iceie coloratum ; mesothorax maris saltern non 

 lineatus ; abdomen fere unicolor ; aim indistincte reticulata, 

 regione subcostali vix colorata, vena subcostali omnino jiava. 



Potamantbus seneus, Pictet, Hist. Nat. Neur. Eph. 229, 10, pi. 33. 

 Switzerland. 



