50 EEV. A. E. EATON ON EECENT EPHEMERID.E OR MAYFLIES. 



Hab. Buenos Ayres {Rag.); the Amazons Eegion {Walk.); Espirito Santo (M^'Lach. 

 Mus.). 



Hexagenia mexicana, sp. nov. 



Imago, 6 {dried). — Wing-membrane transparent pitch-brown throughout, with black 

 neuration, the hind wings rather the darker pair; most of the longitudinal nervures and 

 cross veinlets are narrowly bordered with blackish, and this edging is widened along the 

 cross veinlets in the midst of the wings ; but the costa, subcosta, and radius, with their 

 interjacent cross veinlets are not bordered in the fore wings. Tliorax opaque pitch- 

 brown ; the pronotum with a broad longitudinal black stripe on each side. Abdomen 

 discoloured ; sette brown-black ; forceps pale, blackened towards their extremities. Fore 

 legs with pitch-brown femur and tibia, the tarsus pitch-black ; hinder legs flavescent, 

 the femora towards their distal extremities, the borders of the extremities of the tibia 

 and tarsal joints, the plantar surface, the last tarsal joint and the ungues, tinged more or 

 less with pitch-brown. Length of wing 13 mm. 



Sal). Mexico (Hagen Mus.), captured by Salle; formerly represented in Baron de 

 Selys-Longchamps's collection. 



Hexagenia. bilineata, Say. Plate VII. 11 6, 11 i' & 11 i ? (wings [part] and forceps). 



XBaetis bilineata, Say, Godman's West. Quart. Rep. ii. 303 (1834') ; Lc Conte, Complete Writings of 

 T. Say, i. 203 (1859) .—B. angulata, ! Walk., List of Neuropt. Ins. in Brit. Mus. part iii. 5G4. (1853). 



Ephemera limbata, Serville MS., Guer. Iconograph. Reg. Auim. ii. part I, pi. Lk. 7-9, texte, iii. 384 

 (1829-31) ; Gray, Grif. CI. Ins. ii. pi. xeiv. 7 (1832) ; ! Ramb., Hist. Nat. d. Ins. Nevropt. 295, pi. viii. 

 2 (1842). 



PaUngenia viridescens, ! Walk., o;j. cit. iii. 550 (1853). — P. occulta, ! id., op. cit. iii. 551 (1853) ; Hag., 

 Smitlison. Miscell. Coll. (1861), Synop. Neuropt. N. Am. 43. —P. limbata, id., op. cit. 43 (1861) ; Pro- 

 vancher. Natural. Canad. viii. 265 (1876) ; id., Fn. Ent. d. Canad. ii. fasc. i. 82 (1877). — P. bilineata, 

 Walsh, Proc. Acad. Nat. Sc. Pliilad. (1862), 373; Hag., Proc. Ent. Soc.Philad. ii. 174-5 (1863) ; Walsh, 

 op. cit. 189 k 199 (1863). 



Hexagenia bilineata, Walsh, op. cit. ii. 199 (1863) ; ! Etn., Trans. Ent. Soc. London (1871), 66, pi. iv. 4 

 [detail] ; ? Hag. MS., ! Lintar in 10th Ann. Rep. N. Y. State Commission of Fisheries, p. 3, pi. ii. 6 

 (1878). 



Suhimago {dried). — Wings transparent grey, with pitch-black neuration, the longitu- 

 dinal nervures occasionally tinged with broAvn-ochre or bistre-brown close to the wing- 

 roots ; hind wings, as a rule, from just before the tip to the commencement of the inner 

 margin bordered with dark grey in ? , or black in the d , and sometimes with several 

 of their cross veinlets near the midst of the wing edged with a like colour. 



Imago {dried), 6 . — Pronotum bistre-brown, or sometimes pitch-brown, with a broad 

 longitudinal dark bistre-sepia-brown, or sometimes pitch-black stripe on each side, which 

 is extended upon the mesonotum to at least the wing-roots ; mesonotum for the most 

 part rufo-luteous or rufo-piceous, with the peak often pitch-black, and sometimes less 

 rufescent on its hinder slopes, rarely of a uniform pitch-brown throughout ; metanotum, 

 as a rule, pitch-brown, but sometimes rufo-lutescent or even light brown-ochreous with 

 the peak pitch-brown. Abdomen variable in depth of colour and definition of markings, 



