580 EPHEMERIN.E. 



25. Cloeon dimidiata. 



Castaneo-fusca ; prothoracis lateribus puncto ochraceo ; pedibus 

 stramineis. 



Cloe dimidiata, Piclet, Hist. Nat. Neur. Eph. 272. 

 Cloeon dimidiatum, Curt. Phil. Mag. 1834, 121. Steph. Ill Brit. 

 Ent. Aland, vi. 69, 7. 



England. 



26. Cloeon virgo. 



Pallida; oculis nigris ; femoribus anticis apicem versus obscuris ; 

 alls hyalinis. 



Cloeon virgo, Steph. III. Brit. Ent. Aland, vi. 70, 8. 

 Cloe ? virgo, Pictet, Hist. Nat. Neur. Eph. 272. 

 Ephemera virgo? Oliv. Latr. Hist. Nat. Ins. xiii. 98. 



England. 



Genus 6. C^ENIS. 



Oculi remoti, maris simplices. Pedes bene determinati. Alee 

 duse, venis transversis paucis. 



Caenis, Stephens ; Pictet. 

 Ephemera, p., Fabr. 

 Brachvcercus, Curt. 

 Oxycypha, Burin. 

 Ephemerae trisetae, p., Zett. 

 Ccenidae, Neivman. 



Eyes simple in both sexes, and always separated by a broad in- 

 terval : wings two, much rounded on the internal border, fan- 

 shaped, almost without transverse veins: body short and broad: 

 ungues of the tarsi terminated by two small lamina? ; three tail- 

 bristles of equal length, very long in the male, and very short in 

 the female. 



