168.] 91 
st, as it were, of two or three distinguishable groups welded together, 
'erhaps their relations may be indicated by means of punctuation : 
lius — 
Ccenis, Tricorythus, Oligoneuria, (GampsurusJ ; Gampsurus, Polymi- 
vrcys, Palingenia, Pentagenia, Hexagenia, Ephemera; Potamanthus, 
leptophlehia, Ephemerella, Oloeon,Baetis ; (Leptophlehia), Bcetisca, Colo- 
'j,rus, Siphlonurus, Heptagenia. 
Equivalents. 
1st: Wing nervures. 
Costa, Sundevall = margo aloe antica = la costale, Pictet. 
Vas sub-costale, Sundevall = sub-costa = la sous-costale, Pictet. 
Vas radiale, Sundevall = radius ; la mediane, Pictet. 
Vas ulnare, Sundevall= ramus thyrifer,Kolenati = lasous-mediane, 
'ictet. 
Vasa interna, Sundevall =cubitus, Kolenati^ranale,et accessories 
e I'anale, Pictet = veins on the post costa, Walsh, 
[Vas post costale, Sundevall = the anterior margin of the wing 
etween the pterostigma and the cubital point, Haliday, in Libellulidce.'] 
Supplementary veins are such as proceed from the outer margin, 
ut do not reach the root of the wing, nor are derived from the principal 
eins of the wing. 
Supplementary ribs reach the base of the wing. 
2nd : Margins of Wings. 
Margo antica = costa. 
Margo externa = apical margin, M'Lach. 
Margo interna = post costa, Walsh. 
3rd : Divisions of a Vein. 
Primary veins are called ribs, 
Their branches, veins, 
Their subordinate ramifications, veinlets. 
4th : Modes of Division of Veins. 
Divided, separating at the very commencement (e. g. twice divided.) 
Partite, or parted, dividing almost at its origin (e. g. bi-partite, 
ividing into two). 
-Fid, dividing nearly in the middle of its length (e.g. tri-Jtd). 
Furcate, or forked, dividing near its extremity (e. g. bijurcate, 
nding in twc simple prongs). 
Reading : June 6th, 1868. 
