EEV. A. E. EATON ON EECENT EPHEMEEID^ OR MAYFLIES. 55 



reversed ; also in segments 8 and 9 a broad median longitudinal streak from the base, 

 vanishing beyond the middle of the segment before the joining; also a large spot oc- 

 cupying almost the whole of segment 10: beneath, a ventral stripe, dilated in the meta- 

 sternam, but linear in the abdomen, and somewhat blackened at the joinings, extends 

 backwards to the ninth abdominal segment ; the midribs of the perinatal lobes are of 

 the same dark colour. Setxe uniformlv verv light yellow-ochraceous. Eore le^ liirht 

 brown-ochreous, the tibia and tarsus rather lighter than the femur ; ungues, terminal 

 and first joints, and narrowly the distal margins of the other joints of the tarsus, also the 

 distal extremity and the joining at the knee of the tibia, dark Roman-, or warm sepia- 

 brown. Hinder femora yellow- ochreous or light Mars-yellow, changing in transmitted 

 light to dull yellowish-amber colour ; tibite and tarsi lighter ; the terminal joint and 

 lower distal borders of the next two joints of the tarsus very light purple-madder, the 

 larger of the ungues much darker. Wings more of a dull light-yellowish amber than 

 those of the subimago ; their longitudinal neuration light-yellowish ochraceous, or some- 

 times light Mars-yellow, the cross veinlets, and the great cross vein of the fore wing 

 black, as also are the bullfe of the subcosta and radius. Length of body, d 15-18, 

 S 22-23 ; wing, d 15, 2 17-23 ; setae, im. 6 44, ? 27-28 mm. 



ITab. Texas, Dallas, Waco, and W. Texas [Belfrage), in May; Utah Lake (in 

 M"Lacli. Mus. and Mus. Comp. Zool. Cambridge, Mass.). In 1871, having no s im., I 

 failed to distinguish this sjoecies from S. variabilis. 



Hexagenia VARIABILIS (renamed). Plate VII. 11 c (wings, legs and 6 forceps) 

 [H. limbatci]. 



Palinyenia % Umhata, Pict., Hist. Nat. Nevi'opt. ii. Ephem. 146, pi. sii. (1843-5) ; Walk., List of 

 Neuropt. Ins. in Brit. Mus. part iii. 548 (1853); ! Walsh, Proc. Acad. Nat. Sc. Pliilad. (1862), 373; 

 Hag., Proc.Ent. Soc. Philad. ii. 176 (1863) ; Walsh, op. cH. p. 199 (1863) ,—P.X Mlineata, ! Hag., Smithson. 

 Miscell. Coll. (1861), Synop. Neuropt. N. Am. 41. 



Hexayenia [type] % limbata, ! Walsh, Proc. Ent. Soc. Philad. ii. 197 (1863) ; ! Etn., Ent. Mo. Mag. v. 85 

 (1868) ; ! id., Trans. Ent. Soc. London (1871), 65, pi. i. 7 & iv. 8, 3 a [details]. 



Subimago {dried). — Wings of d somewhat greyish, of 2 dull light yellowish, the 

 marginal and submarginal areas of the fore wing coloured more or less intensely with 

 bght bistre-brown or brown-ochreous, and the hind wings in the 6 along the terminal 

 margin from just round the apex of the wing to the commencement of the inner margin 

 bordered with warm sepia-grey : longitudinal neuration yellowish or very light bistre- 

 grey ; cross veinlets black, commonly with dark borders in the usual parts of the wings, 

 these borders narrow and blackish in the fore wing, and rather wider as well as more 

 nearly warm-, or Roman-sepia brown in the hind wings. In some specimens the markings 

 are extensively blurred in the hind wings, imparting a warm sepia-grey cloud to the 

 whole of the membrane excepting at the base of the wing, where the light yellowish tint 

 is stronger than in the fore wing. 



Variation, 2 . — Wings free from markings ; the membrane uniformly light bistre-grey, 

 very faintly tinted with yellowish in the hind wings ; cross veinlets in most of the disk 

 of the fore wings, and those in the hind wings less decidedly blackened than in the d ; 



