2G6 EEV. A. E. EATON ON EECENT EPHEMERID.E OR MAYFLIES. 



Median caudal seta subequal to the others, about If as long as the body, and beset at the 

 joinings on both sides nearly throughout with minute spreading pubescence, while they 

 are similarly beset on the inner side only. Pronotum well defined, sinuate in the middle 

 posteriorly ; its lateral borders scarcely at all dilated, nearly straight, but rounded off 

 slightly in front. Fangs of the mandibles strongly dcA^eloped, subequal, inflected and 

 compressed; the exterior somewhat triangular, acute, serrulate along the upper edge; 

 the interior fang bifid; endopodite absent, represented perhaps by a minute tuft of hair 

 in the left mandible, and a single short hair in the right. Lacinia of maxilla i. beset at 

 the outer edge of the crown with flattened pectinate teeth, and terminated by two con- 

 tiguous flattened spines at the point ; fii'st joint of the palpus stout ; terminal joint 

 slender, slightly clavate, oblique and velutinous at the end, and pungent at the point. 

 Median lobe of the tongue obtuse and somewhat hexagonal ; paraglossiB broadly 

 expanded, almost oval, not recurved at the tips. Femora marked on the coloured side 

 with a pair of large opposite confluent spots, forming an irregular distal band, and a 

 pair of separate longitudinal opposite streaks near the base, sometimes connected with 

 the band bv dark colourini? alons: the edijes of the femur. 



NORTH AMERICAN SPECIES. 



Heptagenia flavescens, Walsh. 



t Palingenia flavescens, ! Walsh, Proc. Acad. Nat. Sc. Philad. (18G2) 373 ; Hag., Proc. Ent. Soc. Philad. 

 ii. 177 (18G3). 



Heptagenia [type] flavescens, ! Etn., Ent. Mo. Mag. v. 90 (1808) ; id.. Trans. Ent. Soc. London (1871) 

 112, pi. vi. IG [detail ill drawn] ; Hag., op. cit. (1873) 404; ! Etn., Ent. Mo. Mag. xviii. 24 (1881). 



Subimago. — Wings slightly tinged with fuscous in s ; in ? subflavescent, subopaque, 

 with yellowish neuration, " except on the disk and tip," [where doubtless they are 

 fuscous]. SetfG of 6 dull greenish ; of ? pale, a little fuscous at the tips. 



Imago, d. — Yellowish. Eyes bright greenish yellow during life. Notum ferruginous, 

 sometimes verging upon piceous. Dorsum of abdomen ferruginous, darker at the tips 

 of segments 2-7, and with a pair of subobsolete pale vittse at the base of each of them; 

 venter pale greenish in segments 2-7 or -8. Setae whitish ; the joinings fuscous, and 

 sometimes towards the roots alternately "white" [wide?] and narrow. Forceps pale, 

 at the tips fuscous. Fore leg pale ferruginous, with a median and a terminal baud on 

 the femur, the tip of the tibia, and the tarsal joinings and tips fuscous. Hinder legs 

 yellowish, Avith the tips of the femora fuscoiis, and the tarsal joinings and tips a little 

 cloudy. Fore wdng hyaline, with a pale ferruginous cloud iu the pterostigmatic region ; 

 neuration fuscous, excepting the basal § of the costa, subcosta, and radius, which are 

 yellowish ; the thickening at the bulla of the subcosta, about 0'5 mm. long, is more or 

 less obfuscated. $ paler than 6; vertex and notum rather luteous than ferruginous; 

 dorsum of the abdomen pale fuscous or pale ferruginous, without any pale vittie. Setae 

 in one specimen uniformly whitish. " The costal cross veins are hyaline on their basal 

 |." Length of body 9-13; wing 11-15; setne, d im. 27-38, subim. 17, 2 im. 27-28, 

 subim. 13 mm. 



Hab. Rock Island, 111. [After Walsh.] 



