BENGTSSON, AN ANALYSIS OF DESCRIB. SCANDIN. EPHEMERIDA. 15 



even this interpretatioti can not be correct, because it is in- 

 compatible with »abdomine albo» and »pedes . . . albi». Every- 

 thing in the description hetter 8.ip])]ies to C cenis horaria (his.) 

 (=C dimidiata Steph.), imago J". 



6. Eph. brevicauda (1. c. pag. 69. N:o 7). — The descrip- 

 tion completely applies to Cceyiis horaria (Lin.), subimago, 

 and accordingly the species is the same as N:o 6. Eaton, 

 Wallengren and others have interpreted it as identical with 

 Ccenis macrura Steph., but this is incompatible with >>ab- 

 domen palHdum, basi fuscescens» and »pedes pallidi» in the 

 description. 



7. Eph. venosa (1. c. pag. 70. N:o 8) is somewhat dubions. 

 Fabricius says about its occurrence »habitat in Danise palu- 

 dosis», wherefore it cannot be referred to Heptagenia {Ec- 

 dyurus) venosa auct-, as this species has not been found in 

 Denmark. Fabricius himself identifies it with De Geer's 

 species N:o 4. It also seems to me most probable, that it 

 is this species, i. e. Ecdyurus f usco-gr iseus Ri^Tz.^ \Yith which 

 Ecdyurus volitans Eaton is identical. It seems, however, not 

 to be excluded, that it may have been smaller individuals 

 of a Siphlurus. 



8. Eph. hioculata (1. c. pag. 70. N:o 9). — The words 

 »capite tuberculis duobus ...» indicate a J", as also »alis 

 albis» an imago. Both Pictet- and Eaton ^, as well as al- 

 ready Fabricius himself regarded it as identical with Linné's 

 species with the same name. To this the character »caudse 

 albse, fusco punctatse» is opposed, because those in the Lin- 

 nean species are one-coloured white, and therefore the species 

 is dubious. 



9. Eph. nigra (1. c. pag. 70. N:o 10) is possibly identical 

 with Ltnné's species of the same name. 



10. Eph. fuscata (1. c. pag. 70. N:o 11) is scarcely the 

 same species as Linné's E. fuscata, i. e. Baetis hioculatus 

 auct., as it has commonly been regarded. It seems to me 

 that the character »corpus medium» more likely points to 

 a Cloeon. About the colour of the setae nothing is said. 



11. Eph. horaria (1. c. pag. 71. N:o 13). — Under his spe- 

 cies N:o 6 Eph. halterata Fabricius says »nimis affinis videtur 



^ A. J. Retzius, 1. c. pag. 57. N:o 183. 

 ■^ 1. c. pag. 244. 

 ^ 1. c. 



