82 
AN OUTLINE OF A RE-ARRANGEMENT OF THE GENERA OF 
EPHEMEBID^. 
BT A. E. EATON, B.A. 
The principal object of the present communication is the settle- 
ment of the generical nomenclature of the Ephemeridce. Their geo- 
graphical range is only subordinate to the design ; for so circumscribed 
are the sources whence information on this subject is obtainable, that 
it would not be worth one's while to treat of this alone. Doubtless 
the unsightly appearance of the dried insects has something to do with 
the carelessness with which they are regarded by most collectors, and 
with the scantiness of our knowledge of their distribution. My notes 
are limited to the recent genera ; and, unless the contrary is specified, 
the neuration of the anterior wings alone is taken into consideration. 
The terminology of the neuration is that of Sundevall, as elucidated in 
his paper, " Om Insekternas Estremiteter," in the Stockholm Transac- 
tions for 1862. 
Genus C^nis, Steph. 
Syn. Brachycercus, Curt. ; Oxycypha, Burm, &c. 
Type O. macrura, Steph. 
Distrib. — England, Austria, Sweden, Switzerland; N. China, 
Ceylon ; Indiana, Elorida. 
Genus Teicobtthus,* nov. gen. 
Syn. Ccenis, p., Pict. 
Type T. varicauda, Koll. Mss. ; Pict. 
Distrib. — Egypt. 
The type of this genus differs from CcBnis in the neuration of the 
wings. The anterior rib of the vas ulnare is bipartite. Its posterior 
division is simple ; but the anterior vein gives off an alternately pin- 
nate, three-branched veiulet backwards and outwards, near its middle, 
and forks at the commencement of its apical fourth. These nervures 
are connected together by numerous cross-veinlets. The second ulnar 
rib is either bipartite (Savigny, fig. 6), or completely divided {Id. fig. 7), 
and each of the resulting veins sends two simple veinlets backwards to 
the outer margin. The anterior vas internum is simple ; the posterior 
emits two or three simple veinlets backwards (see Savigny, in " Descrip- 
tion de I'Egypte," ii., Nevropteres, tab. 2, figs. 6 and 7). No posterior 
wings. 
Tncorythui (Gr.)— tri-Koruthos = triple-plumed. 
