EEV. A. E. EATON ON EECENT EPHEMEEID^ OE MAYELIES. 53 



aud Texas northwards, and from the Atlantic to the Pacific. June (or May in the 

 South) to September. 



Hexagenia mtjnda, sp. nov. 



Imago {dried), 6 . — Thorax above light raw-umber, with a broad pitch-brown or intense 



sepia longitudinal stripe on each side of the pronotum, narrowly and less distinctly 



produced backwards nearly to the peak of the mesonotum ; the tegute of the fore winf-s 



and the pectus and sides of the pro thorax, together with the fore coxae, yellow ochreous ; 



metanotum partly piceous ; intermediate coxse in front and the fore part of the meso- 



sternum piceous, or intense warm sepia ; a lighter spot of the same colour occupies the 



joining of the meso-, and metasternum. Abdomen very light yellow ochraceous, marked 



Avith pitch-black above, and light burnt-umber beneath : the dorsal markings in segments 



1-7 are a pair of broad stripes rising obliquely upwards from the base of the dorsum near 



the anterior lateral angles, one on each side of the back, rounded oif posteriorly just 



before the distal border of the segment, and joined to each other in front and behind by 



a streak (in the anterior segments), or narrow band (in the hinder segments), of the same 



colour as the stripes, running respectively parallel with and adjacent to the joining and 



the apical border of the segment, — in short, a mark like the letter U closed by a line across 



the top, with arms of ecpial thickness ; in segment 7 a broad longitudinal stripe occupies 



the middle of the space thvis enclosed, whereas in the preceding segments only the dorsal 



vessel is there \-isil)le as a greyish line : segments 8 and 9 differ from segment 7 in their 



markings failing towards the anterior lateral angles of the segments. Ventrally, in 



segments 1-7, a light burnt-umber spot semielliptical in the hinder, but in the form of 



a small segment of a circle in other segments, extends almost across the whole of the 



apical border of each somite, and thence forwards no farther than the midst of the 



segment at the utmost, and that only in the anterior segments : in segments 8-10 the 



predominant colour is bright light brown-ochreous ; the ganglionic track is blackened at 



the base of every segment. Setae intense bistre-brown, lighter close to their insertion, 



their joinings very light, and some of their joints lighter anteriorly than at their distal 



extremities. Eore legs from the trochanter to the fi.rst tarsal joint pitch-brown, the 



trochanter and base of the femur lighter on their inner side ; the intermediate tarsal 



joints pitch-brown distally, but warm sepia-grey in their proximal halves. Hinder legs 



light yellow-ochreous in opaque view, changing to very light yellow amber in transmitted 



light ; the ungues, terminal joint, and the distal border of the penultimate joint of the 



tarsus warm sepia-brown or intense burnt-umber. Wings transparent, almost uniformly 



tinted with extremely light bistre-grey ; the marginal and submarginal areas of the fore 



wing distinctly bistre-grey ; the terminal margin of the hind wing very narrowly tinged 



witli light greyish : longitudinal neuration bronzy raw umber-brown, becoming light 



yellowish at the wing-roots, and in part appearing black in certain lights ; cross veinlets 



black, bordered narrowly with blackish in the same parts of the wings as in H. hilineata. 



Length of body 18 ; wings 14 ; setae 35 mm. 



Kah. Morganton N. C. (Mus. Comp. Zool., Cambridge, Mass.). 



