EEV. A. E. EATON ON EECENT EPHEMEEID.E OE MAYFLIES. 175 



Type. C. luteolum (in Ephemera), MiiUer. 



Distribution. Eurojie ; Hudson's Bay Territory, Arizona, and Cuba. 



Etymology. Kevrpd^Toc and ■n-riAo.-, from the usual spur-like form of the costal jirojection 

 of the hind wing. 



The nymph of the typical species was identified by observation in the field ; but probably 

 I reared it also. The older description was based upon specimens in ill condition, still in 

 my possession. The foremost tracheal branchiae were described as " subulate ; " but this 

 was due to their having been deformed by the preservative fluid. , 



Centroptilum luteolum, Midler. PL XVII. 30 « (wings, d , head tfc forceps). 



Ephemera luteola, MiilL, Zool. Dau. Prodr. 113 (177G). — E. caudata, Strom, N. Saml. Kongl. Dansk. 

 Vidensk. Sflsk. Skrift. ii. 91 (1783) ; Wallengreii, Christ. Vidcusk. Forliandl. No. ii. 21 (1880). 



Cloeun ochraceum, ! Steph., 111. Brit. Ent. vi. 68 (1835); Walk., List of Neiiropt. Ins. iu Brit. Mus. 

 part iii. 578 [C. ochracea] (1853).— C hyalinatum, ! Steph., 111. Bnt. Ent. vi. 69 (1835) ; Walk., List 

 &c. 579 [C. hyaUnata] (1853).— C. albipeime,\ Steph., 111. Brit. Ent. vi. 69 (1835; ; Walk., List &c. 

 579 [C. albipennis] (1853).— C. trmisludda, Walk., op. cH. 574 (1853).— C. haUerata, id., 577 (1853). — 

 C. Ibioculutam, Ilag., Ent. Ann. (1863) 31; ! Etii., Ann. & Mag. Nat. Hist. (3) xviii. 117, fig. [hind- 

 wing] (1866). 



Cloe halterata, Burm., Haudb. d. Ent. Bd. ii. Abth. ii. 798 (1839); ! Ramb., Hist. Nat. d. Ins. Ne- 

 vropt. 299 (1812).— 6'. translucida, ! Pict., Hist. Nat. Nevropt. ii. Ephera. .255, pi. xl. 3, 1 (184.3-5).— 

 C. ochracea, hyaUnata §- albipentiis, Pict., op. cit. 271 (1843-5). 



Baetis luteolus, ! Etn., Ent. Mo. Mag. v. 88 (1868). 



Centroptilum luteolum, ! Etn., op. cit. vi. 132 (1869) ; ! id., Trans. Ent. Soc. Loudon (1871) 108, 

 pis. ii. 8 [part of fore wing] & v. 13, 13 a [details] ; Hag. & Etn., op. cit. ( 1873) 400 ; Mcyer-Diir, Bull. 

 Soc. Ent. Suisse, iv. 310 (1874) ; Rostock, Jahresb. d. Ver. f. Naturk. Zwickau, 1877, p. 86 (1878). 



Snhimago {lichig). — Wings very faintly grey-tinted, sometimes very slightly tinged 

 with the palest yellow-ochre. Peniora light yellow-ochre, tibiae cinereous, tarsi dusky. 

 Setae greyish white or cinereous. 



Imago {living). — 6 . Turbinate eyes bright light red ; lower eyes subolivaceous. 

 Notum either bistre-, or pitch-brown, or black. Abdomen vitreous in segments 2-7, 

 spotted faintly with raw sienna (furfuraceous) on each side near the tips of the dorsal 

 segments, or sometimes wholly of that colour thereabouts ; the other segments opaque, 

 rich brown-ochre, raw sienna, or bistre-brown above, with the distal edges of segments 

 8 and 9 yellow-ochreous ; beneath pale, tinged with very light Mars-yellow distally. 

 Setae and forceps white. Femora cretaceous ; tibiae and tarsi greyish, or smoky white. 

 Wings vitreous ; longitudinal nervures faintly tinged with yellowish. 



? . Eyes olivaceous, greenish black, or black. Notum bistre- or olive-brown. Abdo- 

 men above cither raw sieuua (sometimes modified with light yellow-ochre) or Mars- 

 yellow, or olive-brown, with dark subcutaneous tracheaB in segments 2-6 ; venter pale. 

 Setae white or greyish white. Eemora either light greenish yellow, banded almost im- 

 perceptibly in the middle with reddish (this band is invisible in dried specimens), with 

 the tibiae and tarsi olive-grey ; or femora light yellowish, tibiae and tarsi greyish white. 

 Length of body 5-7; wing G-7"5 ; setae, <s im. 10-14., subim. 7, 2 im. 8-9, subim. 6 mm. 



Hub. Europe from Uammerfest and Alten to Portugal and N. Italy : also N. America, 



