EEV. A. E, EATON ON EECENT EPHEMEELD.E OE MAYFLIES. 131 



as long as wide, and has the prsBscutum half as long again as wide instead of scarcely- 

 longer than wide. Sternum ferruginous, legs immaculate, hut the tip of the fore tibia 

 and the adjacent joint of the tarsus in the d fuscous. Length of body, <d 5, sets about 

 5 ; expanse of wings 14 millim. 



Hab. Hock Island, IlL Described from a single defective specimen. 



Several undescribed North- American species of Ephemerella are scantily represented 

 in the collections referred to, which it seems undesirable to characterize. 



Ephemerella elongatula, M'^Lachlan. 



Lepiophlebia elongatula, ! M'Lach., Trans. Eut. Soc. London (1875), 169 (pai-t). 



Imago {dried), $ . — Body intense jecinoreus. Sette blackish fuscous. Wings vitreous, 

 with the costal margins of the fore wings narrowly brownish yellow ; neuration fuscescent, 

 the longitudinal nervures towards the wing-roots, and the proximal halves of the sub- 

 costa and radius of the fore wing, yellowish. Length of wing 14 millim. [Abstracted 

 from M^Lachlan's description.] 



Sab. Yokohama (Pryer, in Wormald's Mus.). The ? subimago attributed to this 

 species in 1875, prolmbly through an error on my part, is apparently a Meptageuia. 



Five Nymphs allied to Ephemerella, sedis incertce. 



Nymph No. L— PI. XXXVIII. 1-10 (whole figure & details). 



Perhaps an Ephemerella, but differing from the nymph of the typical form in the 

 following particulars. Abdomen broadest in front, tapering gradually to the end of the 

 9th segment ; the plevirse nearly straight along their outer sides, their hinder corners in 

 segments 4-7 nearly right-angled, those in segments 8 and 9 shortly ^^rolonged into acute 

 triangular points ; a line drawn touching the outer edges of the pleura? on each side 

 would be curved only in a very slight degree. Tracheal branchite obtusely rounded off 

 distally. Anterior, or inferior, edge of the fore femur minutely denticulated. Joints 1 

 and 2 of the palpus of maxilla I. subequal to each other ; joint 3 rather shorter. Length 

 of body 8-5, setie C millim. 



Uah. AVashington Territory ; Wenass V., W. T., Taylor's, 6th July ; Klikitat V., 

 W. T., Thorpe's, 10th July, S. Henshaw (Mus. Comp. Zool. Cambridge, Mass.). 



Nymph No. II.— PI. XXXVIII. 11-1.5 (whole figure & details). 

 Perhaps an Ephemerella, tuberculate on the vertex of the head and the notum, and 

 with rows of spines instead of tubercles on the dorsum ; also with tlie abdominal plem-ae 

 wider than in the typical species, and the proximal joint of the palpus of maxilla i. rela- 

 tively longer. — Head vertical, with an erect elevated and acute triquetrous tubercle on 

 each side of the crown above the inner orbit of the oculus, terminating a low blunt ridge 

 ascending in a curve from near the posterior ocellus, and with a small rounded wart-like 

 protuberance on the vertex, intermediate between that and the median longitudinal 

 ridge ; occipital border slightly prominent. Pronotum narrower in front than behind, 



