1868.] 



91 



aist, us it were, of two or three distinguishable groups welded together. 

 Perliaps their relations may be indicated by means of punctuation : 

 thus — 



Ccenis, Tricorythus, OU^oneuria, (CampsurusJ ; CampsuruSj Polymi- 

 tarcySj Palingenia, Pentagenia, Hexagenia, Epliemera ; Potamanthm^ 

 Leptophlehia, Ephemerella, Cloeon,Baetis ; (Leptophlehia) ^ Bcetiscaj Colo- 

 hums, Siphlonurus, Reptagenia. 



Equivalents. 

 1st: Wing nervures. 

 Costa, Sundevall = margo ala? 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 = la sous-mediane, 

 Pictet. 



Vasa interna, Sundevall =cubitus, Kolenati==ranale,et accessories 

 de I'anale, Pictet = veins on the post costa, "Walsh. 



[Yas post costale, Sundevall = the anterior margin of the wing 

 between the pterostigma and the cubital point, Haliday, in Lihellulidce.l 



Supplementary veins are such as proceed from the outer margin, 

 but do not reach the root of the wing, nor are derived from the principal 

 veins 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 rils, 



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, 

 dividing into two). 



-Fid, dividing nearly in the middle of its length (e. g. tri-Jid). 



'Furcate, or forked, dividing near its extremity (e. g. bijurcate, 

 ending in two simple prongs). 



Reading : June 6^7^, 1868. 



