EEY. A. E. EAIOX OX EZCZXT EPHEMEEIDJ: OE ilATTLIES. 253 



Rhitheogeva MAXirESTA (renamed). 



; Baitis \\ debilis, ! Walsh, Proc. Acad. Nat. Sc. Philad. (186.2) 371 ; Hag., Proc. Ent. Soc. Philad. ii. 

 170 (1863) [nee. ; B. debilis ! Walk. 1853; neque B. \\ debilis ! Walk. JCI. debilis) I860]. 

 X Siphlwrus debilis, Etn., Trans. Ent. Soc. London 1,1871) 130. 



Subimago. — "Wings fumose, with fuscous neuration. Setae cloudy at tlie tips. Fore 

 tarsi fuscous. 



Imago {living), 6 . — Eyes broTm above, fuscous in their loivest ^. "N'otiim generally 

 piceous. Dorsum of abdomen ferruginous, with the distal f-4 of each segment more or 

 less piceous. Setfe uniformly whitish ; forceps pale. Legs pale greenish ; the femora 

 with a narrow median band [r thia longitudinal streak" and generally the knee fuscous ; 

 the tip of the fore tibia, the tips of the tarsi, and the incisures of the fore tarsus fuscous. 

 "Wings hyaline ; neuration pale greenish hyaline, excepting the basal | of the costa, sub- 

 costa, and radius, and occasionally their tips, which are fuscous in the fore win». 



2 . Paler than d ; thorax almost yellow. Abdomen ferrusinous, usually darker 

 at the tip of every joint. "Wing-veins dusky along the costa and at the tip of the 

 fore wing, jradually becoming hyaline as they approach the anal angle. Length of 

 body 4-7 ; wing 5-7 ; setae, <s im. IS-li, subim. about 5, 5 im. 8-ll"5 mm. 



Sab. Eock Island, 111. [after "Walsh]. "Why "Walsh should have supposed this insect 

 to be m.ore nearly related to Siphlunis than to Septagenia is inexplicable. 



Ehitheogexa hagexi (renamed). Plate XXIT. 43 c (penis dried). 



Heptagenia |1 brunnea, ! Hag., Ann. Rep. U. S. Geolog. &: Geograph. Snrvey of the Terr. 1873, 

 part iii. Zool. 581 (1875) [ J im. only]. 



Imago [dried), d . — Thorax abo^e bright-brown ochreous, the peak of the mesonotum 

 flavescent, a line adjacent to the tegulse and a streak below it in front of these in a 

 depression broAvn-black. Abdomen above pitch-bro-mi, the tips of the segments darker ; 

 venter rufescenti-lutescent, spotless ; setae sepia-brown, with most of the joinings opaque. 

 Porceps pitch-brown. "Wings ritreous, the fore wings almost imperceptibly tinted with 

 li^ht sepia-grey in the pterostigmatic space ; their marginal area contains 4 or 5 cross 

 veinlets before the bulla, then 5-7 simple, followed by 11-14 irregular cross 

 veinlets anastomosing with one another nearer the costa than the subcosta ; neuration 

 pitch-brown, paler just at the wing-roots. Fore legs fuscous, the tibiae and tarsi piceo- 

 fuscous; hinder less luteo-fuscescent, their tarsi slightly browner or warm sepia; every 

 femur in its proximal half is marked with a longitudinal brown-black streak tapering at 

 both ends. Length of body 10, wing 13 mm. 



Sab. Nevada, Truckee in the Sierra Nevada, June 10 (G. E. Crotch). 



EhITHROGEXA EliEGASTTLA, sp. nov. 



Subimago {dried). — "Wings as in Heptagenia snlphiirea, extremely pale yellowish ochre, 

 with concolorous neuration. Setae dull whitish, with the joinings narrowly reddish. 

 Tarsi slishtly tinged with brownish, approaching bistre-brown; the joinings seem opaque 

 only in transmitted li^ht. The femoral bands ai-e faintlv defined. 



SECOND SERIES. — ZOOLOGT, VOL. HI. 34 



