44 EEV. A. E. EATON ON EECENT EPHEMEEID^ OE MAYFLIES. 



Ephem. pi. xi. Kymph, PI. XXVIII. (whole figure and details) ; see also citations tinder 

 P. virgo, especially of Reaumur (1742), Joly (Sept. 1876 and 1878), and Vayssifere 

 (1882). 



Adult. — Discal cellules of the fore wing small and subquadrate ; in the vicinage of 

 the terminal margin the axillary nervures and the proximal branch of the anal nervure 

 are strong, but in the neighbourhood of the fork of the anal nervure the neuration often 

 assumes a feebler and rather closely reticulated texture ; the nervures interposed between 

 the anal (8) and pobrachial (7), or some of them, are liable to lose themselves in this 

 reticulation on approaching the basis of the anal nervure, and nowhere in the wing are 

 the nervures especially fasciculated. Pore leg of 6 about as long as the head and body 

 together, the tarsus much (3-5 times) longer than the femur, which is not \ as long as 

 the tibia ; the ungues nearly coequal, narrow, long, and flaccid. Aperture of the anterior 

 thoracic spiracle ovate, narrowed below ; that of the posterior spiracle ovate, narrow and 

 elongate. Setae in d 2, in $ 3, equal ; in the former sex about three times as long as 

 the body, glabrous from the base nearly to the tip, and divaricate in the dried insect ; 

 in ? about f as long as the body, and pubescent. Eyes of s relatively small, oval, 

 mutually remote ; anterior ocellus much smaller than the others, which are unusually 

 large in comparison with the eyes. Eorceps-limbs sessile upon the border of the seg- 

 ment ; the proximal joint short, somewhat compressed ; second joint the longest. Penis 

 exposed, the lobes straight, unarmed. Hinder lateral angles of the abdominal segments 

 subrectangular. Isymph fossorial ; mandibles tusked ; fore tibia strongly bearded and mi- 

 nutely tuberculated behind, spurless ; seven pairs of abdominal tracheal branchiaj inserted 

 each on a lateral protuberance, armed with a minute tooth-like tubercle, situated a little 

 in advance of the hinder lateral angle of the segment, arched upwards over the back ; the 

 first of the series different from the rest, being single, spathulate, and fringeless ; the 

 others mutually alike, double, with uniform unequal divisions, — each moiety a rather 

 narrow, blunt, membranous lamina, folded together lengthwise once, and fringed with 

 short simple fibrils. Setse about \ as long as the body, plumose in the greater part of 

 their length, and then tail-2:)ointcd. Palpi of both maxilla; 2-jointed. — Head hard, about 

 as broad as the thorax ; pronotum quadrangular ; terminal margins of the fore wings 

 free ; body soft and tender. Antennas setaceous, many -jointed, the first 2 joints stouter 

 than the others. Labrum well developed, subquadrangular, rounded in front. Tusks of 

 mandibles about twice as long as the head, echinate iipon the upper surface, slightly 

 connivent distally, each with a well-defined ensheathing beard of long spreading hair 

 inserted in a curve on the outer base, also with a dense patch of shorter hair just at 

 the commencement of the tubercles, and with some sparse pilosity over the rest of the 

 upper side ; the crown and lobes (or fangs) nearly at right angles with the tusk. 

 Lacinia of first maxilla subquadrangular, widened from the base to the obliquely truncate 

 crown, acvitely pungent, ciliate at the inner margin, and crowned with a dense long 

 beard : palpus stout and long ; the first joint nude, and about \ as long as the second ; 

 second joint externally pilose, on the inner side strongly bearded, tapering from the middle 

 to a point, and slightly curved. Lacinia of second maxilla broadly ovate, oblique, densely 

 pilose : palpus stout ; first joint nearly § as long as the other, pilose outside in the 



