British Ephemeridce. 7 



11. SiPHLONURUS LACUSTRIS, n. sp. 



(^ . Eyes sooty-black. Thorax black above, polished. 

 Wings clear, with piceous venation ; the tips of the mar- 

 ginal and submarginal areas slightly discoloured. Fore- 

 femora blackish green, tibiee and tarsi corvinous ; hinder- 

 legs dark greenish-gray. Abdomen coloured much the 

 same as that of 8. armatus ; the last segment however is 

 unarmed. 



Length of body, S 15 j fore- wing, 14; set. 20 mm. 



Hab. — Llyn Llydaw, Snowdon. August. 



12, Heptagenia volitans, n. sp. 



c?. Eyes fusco-piceous above. Thorax above atro- 

 fuscous. Wings clear, with blackish venation ; the tip 

 of the marginal area slightly discoloured. Fore-tarsus 

 and tibia fuscous, the femur has two faint rings ; hinder 

 femora dull testaceous, with two carneous rings, tibiae 

 sometimes testaceous, tarsi fuscous. Abdomen fuscous 

 above, with the tips of the segments darker; beneath 

 dark greenish-gray, usually spotless. Setee pale greenish- 

 gray, with darker joinings. 



Length of body, c? 12-15; fore-wing, 13-14; set. 25- 

 28 mm. 



Hab. — The Thames just above Pangbourne, and the 

 Holy-brook near Coley Park, Eeading. May. 



It differs abundantly from the cJ imago of H. jiavi- 

 jpennis, which has green eyes, and the thorax furfurose 

 above. 



The HeptagenicB tower like a hawk when there is a 

 slight breeze blowing. In allusion to this habit I have 

 named this species volitans, 



13. Heptagenia insignis, 



Baetis montana, Hag. Ent. Ann. 1863, p. 26 {nee Pict.) , 



c? and 9 . Eyes sub -olivaceous, intersected by a hori- 

 zontal fuscous streak. Thorax above fuscous or sub-oli- 

 vaceous (piceous in dried specimens) . Wings clear, with 

 piceous nervures : bases of the marginal and submarginal 

 areas slightly discoloured, their tips blackish. Fore-legs 

 atro-piceous or corvinous ; hinder legs sub- olivaceous or 



