170 
Psyche 
[October 
A NEW GENUS OF MAYFLIES FROM THE MIOCENE 
OF FLORISSANT , COLORADO. 
By T. D. a. Cockerell. 
University of Colorado, Boulder, Colo. 
Among some fossil insects from Florissant kindly loaned 
by Director J. D. Figgins of the Colorado Museum of Natural 
History, I find a very fine Ephemerid belonging to the Siphlonu- 
ridse* and apparently referable to an undescribed genus. Banks, 
in 1907, treated Chirotonetes and Ameletus of Eaton as synonyms 
of Siphlonurus. On this broad basis the fossil might also be 
referred to Siphlonurus] but more recent authors have re- 
cognized Eaton’s segregates, and from this point of view Siph- 
lurites forms a sufficiently valid genus. In the description, I 
have followed Tillyard’s revised nomenclaturef, but it should 
be understood that Tillyard’s first and second cubitus are 
Comstock’s first and second anals (following Miss Morgan) ; 
Tillyard’s media is Comstock’s cubitus, and Comstock’s media 
is considered part of the radius. In Needham’s key to the genera J, 
Siphlurites runs out on p. 25 at ff, forming a third section as 
follows : 
fff. The intercalates between the first aud second anal veins (of 
Needham and Comstock) represented by a pair of veins, 
the first simple, the second forking, from the first anal to 
the wing margin, and a third vein which bends and runs a 
long course parallel with the first anal, emitting below about 
nine simple veins to the margin Siphlurites. 
Siphlurites new genus. 
Anterior wings with costa somewhat arched basally, the 
costal area broadened, so that its depth is I mm., gradually 
decreasing apicad; transverse veins of costal area numerous 
*Tillyard writes Siphluridae, but Eaton named the type genus Siphlonurus in 1868, and 
was not at liberty to alter it to Siphlurus in 1871. 
fTransactions New Zealand Institute 54. (1923) p. 227. 
JBull. 86, New York State Museum (1905) pp. 23-26. 
