868.] gi^ 
Section B, L.fusca, Curt. 
Distrib.— England, Switzerland, Austria (Carniola), 2 sp. 
The posterior wing has the costa curiously excised in its apical 
lalf ; aud the basal joint of the forceps, instead of being upwards of 
hrice as long as the other two together, equals them in length only. So 
ang as the subaqueous stages of development remain unknown, it seems 
dvisable to retain the species in the geuus Leptophlehia. 
Genus Ephemeeella, Walsh. 
Syn. Potamanthus, Pict., part. 
Baetis, Walker, part. 
Type E. exerucians, Walsh := invaria, Walker. 
Distrib. — Hudson's Bay, Illinois, 2 sp. ; England, Spain, Switzer- 
md, Germany, 3 sp. 
The neuration differs from that of Leptophlehia principally in the 
illowing particulars. The foremost vas internum, instead of curving 
)rwards when it nears the base of the wing, and thus receding from 
le second vas internum, runs straight up to the thickened root of the 
ing alongside the second : it gives off a bipartite vein, and is itself 
ifurcate. The second vas internum is simple, the third bipartite, and 
Qited with the second by a cross-veinlet. The ^ has 3-jointed forceps 
(vhose second joints are the longest), and ascalaphoid eyes (Mr. Walsh 
lys those of invaria are simple). In its later subaqueous stages of 
jvelopment the immature insect has six pairs of complex branchial 
ipendages, which are made up of a trapezoidal plate furnished under- 
^ath with a bipartite process, which supports several imbricated 
mellae arranged lengthwise. 
Genus Cloeon, Leach. 
Syn. Gloe, Burm., Pict., part. 
Chloeon, Lubbock. 
Gloeopsis, Etn., olim. 
Type C. dipterum, Lin. 
Distrib.— Lapland, Egypt, Madeira, France, Austria; N. China; 
or perhaps 3 sp. A species (1 specimen in Brit. Mus.) is reputed 
be from S. Australia. 
Dipterous. During their later aquatic stages of development the 
sects have six double pairs and a seventh single pair of branchial 
ates. A series of short, solitary, supplementary veinlets is situated 
