о 
ESBEN-PETERSEN. 
the nymphs of Sparrea norvegica and Metretopus norvégiens. They were previously 
described by Dr. S. Bengtsson, to whom I am also very thaukful for bis generosity 
in presenting to me materials of several imagines and larvæ described in bis «Beiträge 
zur Kenntnis der paläarktiseben Ephemeriden». 
A. Imagines. 
Fam. Ephemerellidae. 
Tbis family, Section 6 of tbe Genera in A Rev. Mon. of rec. Ephem. or 
Mayflies by A. E. Eaton, contains 3 genera: 2 European-American ( Ephemerelia Walsb. 
and Chitonophora Bengtss.) and 1 Asiatic ( Teloganodes Etu.). Tbe two first named genera 
are separated from eacli other in tbe following way: 
a. Hind femur and tibia about of equal length; hind tibia a little longer than bind 
tarsus. Ephemerella. 
b. Hind tibia mucli longer than hind femur and about twice the length of bind 
tarsus. Chitonophora. 
Genus Chitonophora. 
S. Bengtsson: Beiträge zur Kenntnis der paläarktiseben Ephemeriden, Lund 1909. 
Apart from the différences already pointed out, it may still be noticed tbat the anterior 
tibia of tbe male of tbe Chitonophora is a little longer than femur and tbat tbe tarsus is 
about twice as long as tbe tibia. Anterior tarsus, tibia and femur of the female almost of 
equal length. 2. joint of tbe forceps of tbe male terminâtes in a sharply marked quadran¬ 
gulär dilatation. 
-- ,-4 -t g l. ■ — r^ i -i. 
__ - -, 2i 
4=x x~mr -- — '— i - 3 
Fig. 1. Chitonophora Aroni Eat. Legs of the male. 
The type for the genus is Chitonophora Aurivillii Bengtss. from Northern Sweden, 
and to this genus also belong Chitonophora mucronata Bengtss., from tbe same localities, 
and Ephemerella Aroni Eat. from Norwegian Finmarken and Finland. 
