128 EEY. A. E. EATON ON EECENT EPHEMEEID.E OR MAYFLIES. 



dull light-brownisli yellowish, the fore tarsus and distal portion of the tibia, and in the 

 hinder tarsi the ungues, tip of the terminal joint, and distal borders of the other joints 

 brownish, the brown being sometimes modified with reddish. 



Imago {dried), 6 . — Thorax above polished, and of a rich deep pitch-brown, the anterior 

 half of the mesonotum in one example much lighter in the midst. Abdomen above either 

 pitch-brown, with the last 3 segments rufescent, and the lateral borders of tbe dorsum 

 light yellowish; or dark rufo-piceous, with tlie last segment yellowish; the joinings 

 opaque. Venter lighter than the dorsum ; genitalia light yellowish. Setae whitish sepia- 

 grey, with black joinings. Wings vitreous; the neuration in some lights colourless, the 

 longitudinal nervures in other lights becoming faintly tinged with light greenish grey, 

 changing in other positions to very light amber ; at the wing-roots of the fore wing is, 

 ajiparently, a light pitch-brown spot. Fore leg, as an opaque object, dull greenish grey, 

 with the coxa, trochanter, and knee lighter, the tarsus dirty whitish or greyish white, 

 with the joinings and ungues brownish ; in transmitted light the femur becomes light 

 yellow-amber. Hinder legs in opaque view, Avith the femur and base of the tibia, 

 yellowish amber, the distal portion of the tibia, and the tarsus dirty whitish, the latter 

 liaving the ungues, the end of the terminal joint, and the distal borders of the other 

 joints light reddish-brown. 



?. Thorax above polished brown-ochreous ; the pronotum destitute of raised dots. 

 Abdomen discoloured ; ventral lobe of the 9th segment broadly rounded and almost 

 entire, the pleural points obtuse. Wings as in 6 , but with the longitudinal nervures 

 rather more definitely colovired. Legs very similar to the hinder legs of tlie d , but in 

 one of the specimens only the ungues and not the joinings of the hinder tarsi are light 

 brownish. Length of body, 5-G ; wing, 6-8 millim. 



Hub. Colorado, at Denver, Arkansas Canon, and Colorado Springs (Mus. Comp. Zool. 

 Cambridge, Mass.). 



Ephemekella guamdis, sp. nov. Plate XIV. 2i b (neuration). 



Subimago {dried). — Wings dark sepia-grey, or sometimes of a slightly blacker grey, 

 with dark neuration, excepting at their extreme base, where both nervures and mem- 

 brane are more or less of a dull greenish-yellow, varied witb brownish. Coxa^, trochanters, 

 hinder tibiae and tarsi, fore tarsus, and sometimes the fore tibia very pale reddish 

 (burnt-umber) brown : femora pitch-brown. Setae pitch-black at the base and then 

 sepia-brown. 



Imago, ? [dried). — Thorax bright brown-ochreous. Abdomen shrunken through desic- 

 cation, and discoloured ; in one example the colours along the middle of the dorsum 

 have considerably changed, but on both sides the segments are narrowly bordered 

 with dull ochraceous along the pleurae, and a series of large rounded blotches of a dark 

 purplish brown colour [pitch-brown modified with intense burnt-carmine] occupies the 

 immediately adjoining parts of the intermediate segments (perhaps excepting segment 9). 

 Setaj in opaque view pitch-black near the roots and then pitch-brown ; in transmitted 

 light the black changes to pitch-brown, and the lighter parts appear whitish warm sepia- 

 grey, with rufescent joinings. Ventral lobe of segment 9 emarginate ; the jdeui-al points 



