58 REV. A, E. EATON ON RECENT EPHEMEEID^ OR MAYFLIES. 



and both extremities of the tibia madder-brown ; the rest of the tibia and most of the 

 tarsus in opaque view light brown-ochreous, or in transmitted light yellowish amber- 

 colour, but the ungues, terminal joint, distal borders of the intermediate joints, and the 

 whole of the proximal joint of the tarsus blackish or intense burnt-uinber. Hinder 

 legs and wings nearly as in the lighter variations of the c? , the cross veinlets being 

 immarginate : marginal and submarginal areas of the fore wing uniformly tinted with 

 very light amber-yellow. Length of body, d 14-16, ? 18-24 ; wings, <s 13-15, $ 17-24 ; 

 setse, <S im. 36-46, subim. 23, ? im. 26, subim. 23-25 mm. 



Sab. Widely distributed in the United States : Utah Lake ; Texas ; Lake Harney, 

 Fla. ; St. Louis, Miss. ; Galena and Rock Island, 111. ; New Eed River ; Detroit, Mich. ; 

 New England ; Philadelphia, Penn. ; and Washington, D. C. (Mus. Com. Zool. Cambridge, 

 Mass.; Hag. Mus.; M^Lach. Mus,). 



EPHEMERA, Linn. 1746; restricted, Leacli, 1815. 



Illustrations. Adult, PL VIII. 12 a-d (details) ; (whole figures) see citations under 

 JE. vulgata, danica, lineata, and glaucops, especially those referring to Pictet (1848-5), 

 Curtis (1838), and Stephens (1835). Nynqih, PI. XXX. ; see also citations under 

 E. vulgata of Guerin (1829-43), Gray (1832), Blanchard (1868), and Vayssiere (1882) ; 

 also under E. danica, of Pictet [pis. 1 & 2] (1843-5). 



Adult. — Pronotum in ? somewhat transverse, tumescent above, about as wide as the 

 head behind but narrower in front ; the anteriorly convergent lateral borders slightly 

 constricted at about their first ^, and suddenly rounded off at the angles in front and 

 behind; the arched and sinuous hind margin slightly retuse in the middle, and a little 

 everted at the lateral angles. Pore leg of d about f as long as the body, tibia 2| or 

 3 times as long as the femur, the tarsus about 4 times as long as the femur ; $ fore femur 

 about f as long as the tibia, and subequal in length to the tarsus. Thoracic spiracles 

 straight lipped, relatively smaller than in Hexagenla, usually closed in dried specimens, 

 but sometimes the anterior gapes narrowly. Median seta about as long as the others in 

 both sexes ; outer setae in 6 about twice as long as the body, in s subim. and in ? im. 

 nearly of the same length as the body : under a lens they appear pubescent throughout, 

 and theu' joinings are well marked. Last two joints of forceps limbs well develoi^ed. 

 Lobes of the penis usually flattened, and oblique at the ends through prolongation of the 

 thickened outer lateral border, but deviating from this European type in some exotic 

 species ; stimuli, when present, interior, subulate and slender. Abdominal segments 

 of 2: — 1-4 relatively short, the first thoracoid, 5 rather longer, 6-9 long, 10 short; 

 segment 8 is subequal to 7, and rather longer than 9 ; segment 7 is a little longer than 

 6 ; segments 6-10 together constitute about f of the abdomen. Anterior ocellus much 

 smaller than the others. Eyes of d oval, their inner orbits curved, mutually remote 

 above. Suhhnago quiescent for about 24-36 hours, standing with erect connivent wings 

 upon its hinder legs, the fore legs prorect off the ground, and the setse placed close 

 together, the outer either above or below the median seta. Nymph. — Head narrowed 

 anteriorly, and armed in front with two conical projections ; mandibles tusked, the tusks 



