58.] 
89 
Genus B.etisca, Walsli. 
Syn. Baetis, part., Say. 
Type B. olesa, Say. 
Distrib. — United States. 
The anterior ulnar rib is seemingly tri-partite. (The anterior di- 
isiou is probably a supplementary vein, which, with its foremost parti- 
ion, is bipartite, and includes a simple supplementary vein ; its second 
ivision is simple). The second partition of the first ulnar rib is bifurcate, 
nd includes a simple supplementary vein : its third partition is simple, 
'he simple posterior ulnar rib is succeeded by two supplementary ribs, 
[le hinder of which sends several simple veinlets, parallel one with 
nother, to the internal margin. There are two straight, simple, vasa 
iterua. The forceps of the $ seem to be 3-jointed, and to have the 
Bcond joint the longest, as in Epliemerella (but that which appears to 
e the proximal joining may be a fold in the integument only, in which 
ase the first joint would be by far the longest, and would present an 
btuse spine on its under-surface, like the first joint of the forceps of 
ome s])ecies of Leptophlelia) . A jointless remnant of the central seta 
3 retained. 
G-enus Colobukus,* nov. gen. 
Syn. Paling enia, Burm., part., "Walker. 
Type G. humeralis, Walker. 
Distrib. — New Zealand. 
The vas ulnare resembles somewhat that of the preceding genus in 
ts manner of branching. It is followed by two supplementary ribs, 
md two supplementary veins. The first of these ribs sends down three 
)r four bent, simple (or slightly bifurcate), veins to the internal 
nargin ; the second of them resembles a vas internum. There are 
ibout four, slightly curved, vasa interna, some simple, others bifurcate, 
)r even bifid. The outer setse are upwards of fifteen times longer than 
;he central one. The ^ has 4-jointed forceps, their second joints are 
;he longest ; eyes double. 
Genus Siphlonurtjs,! uov. gen. 
Syn. Baetis, Ed. Pict., part. 
Ephemera, Zett., part. 
Type S.flavidus, Ed. Pict, 
Distrib.— Sweden, England, Ireland, Spain, 1 sp. ; Prussia, 2 sp. ; 
United States. 
» Kolobouros (Or.) = stump-tailed. t SipMeoura (Gr.) = defective in the tall. 
