on the Hphemeride. 99 
duabus punctisque sequentibus duobus apud basin singuli 
segmenti obscure indicatis. Sete fuliginose, juncturis 
saturatioribus ; forceps testaceus. 
?. Oculi flavo-olivacei. Tibiz antice testaces. 
Puncta nodalia alarum eis maris distinctiora. Processus 
ventralis penultimi segmentorum retusus. 
Long. corp. ¢ 8-9; al. 6 9, ? 10-11; set. ¢ 10 &11- 
12 & 11, subim.8&7; set. 9 8&9,subim.7 & 9 mm. 
Hab.—Great Britain, Germany, Switzerland; also 
Madrid (H. Pict. Mus.). Frequents streams and rivers. 
June to September. 
Ephemerella gibba. 
Potamanthus gibbus, Pict. 1843-5. 
Subimago. ‘ Ale saturate grisez, apud bases lutes- 
centes.” 
Imago, v.s. 6. “Oculi acute rubri. Corpus fusco- 
rubiginosum ; alis vitreis ; pedibus fulvis, anticis femori- 
bus tarsisque fuscescentibus ; setis fulvis, juncturis atris.” 
2. “ Pallidior mare; capite thoraceque fulvis, illo 
atro-punctato, punctis super verticem confluentibus, 
hoe punctis parvis duobus fuscis in medio prothoracis 
tergi, et pluribus commissurarum dorsalium mesothoracis 
fuscis. Abdomen rufescens, supra punctis obscuris duo- 
bus in medio segmenti singuli.” —(Pict.) 
Long. corp. ¢ 6-7, ? 7; set. ¢ 9, subim. 7; set. ? 
8, subim. 7; exp. al. ¢ 15-16, ? 21 mm. 
Hab.—A streamlet near Villeneuve, at the head of the 
Lake of Geneva ; in July (Pict.). 
Ephemerella cenea. 
Potamanthus ceneus, Pict. 1848-5. 
Subimago. ‘“ Alze grisez ; antica basi subcoste fulva.” 
Imago, 2. ‘Caput et oculi fulvi, macula supra 
fusca. Prothorax maculi utrinque fusci; mesothorax 
eneus, politus. Al vitrez, iridicolorate ; nervorum 
longitudinales fulvi, transversales grisei. Pedes fulvi, 
juncturis tarsisque nigricantibus. Abdomen olivaceo- 
fuscum ; sete testacez, juncturis atris.” (Pict.) 
H 2 
