238 EEV. A. E. EATON ON EECENT EPHEMERID^ OR MAYFLIES. 



the base ; second joint clavate, obliquely truncate and densely velutinous at the end, and 

 acute at the tip. Median lobe of the tongue subquadrangular, longer than broad; 

 paraglossse obliquely truncate, broadest at about the middle. The dark markings of the 

 femora on the coloui'ed side comprise a pair of short opposite longitudinal streaks near 

 the base, separated by a narrow interval from three other longitudinal streaks, of which 

 the two longer extend to the tip, and the shorter is contiguous with the lower edge ; 

 these three combine partially to form an irregular submedian fascia ; a dot in the inter, 

 space between the basal and distal groups of streaks is coalescent with the lower streak 

 of the former group. 



Type. E. torrentium, Etn. 



Distribution. Europe, Armenia, and North America. A Himalayan insect also is 

 ranked provisionally in this genus. 



Etymology . eVrjojOoc, soaring on high. 



The Armenian and American species, communicated by Dr. Hagen, are undescribed. 

 A single pinned specimen from the former province is in his own cabinet ; and from the 

 latter continent three nymphs in alcohol, exhibiting the normal structure, are in Mus. 

 Comp. Zool. Cambridge, Mass., registered 22(?, Wenas V., W. T., Taylor's 6, vii. 1882. 

 Before Iron and Cinygma were recognized as genera, other specimens than those above 

 referred to were returned as species of Epeorus, Etn. MS. 



The generical identification of the nymph was established by an exhaustive examination 

 of the'fauna of sites in a mill-stream frequented by the imago of E. torrentium at Tarascon 

 (Ariege). The subimago was observed to take flight at places where the water rippled 

 strongly over submerged stones ; the stream was nearly waist-deep, and the strength of 

 the current rendered the employment of a water-net indispeusable to the capture of the 

 nymphs lurking beneath the stones. This mill-stream is close to the highway above the 

 town. 



In insects of this genus the coloration of the body is often difficult to define, owing 

 to the superficial tissues differing in hue from more deeply situated pigmentary matter 

 visible through them. The pattern of the ventral markings affords an easy means of 

 distinguishing the species of adult specimens. 



Epeorus geminus, sp. nov. 



Imago, s . — {dried.) Notum brown-ochreous, darker behind. In each of the ventral 

 segments 3-7 a single narrowly obcuneate, or obovate-lanceolate, dark spot contains before 

 the tip of the segment a pair of pale dots. In dorsal segments 2-8 the terminal margin 

 is dark, excepting at the pleurte, the hinder angles of which are of a light colour ; and 

 the dark colouring is continued from the said margin on each side, descending forwards 

 obliquely in a gentle curve to the main trachea, and, running onwards along it, terminates 

 at the place of the branching-off of the dorsal trachea. — [Living.) Eyes warm sepia-brown. 

 Notum bistre-brown, darker laterally and posteriorly. Dorsal abdominal segments 2-8, 

 light brownish yellow at the base and sides, bordered broadly with pitch-brown along 

 the greater part of the terminal margin, and striped obhquely with the same colour on 

 each side, the stripes descending from the bordering nearly to the middle of the lateral 



