EEV. A. E. EATON ON EECENT EPHEMERID^ OR MAYFLIES. 105 



Nymph latent ; abdominal tracheal branchiae diversiform ; those of segment 1 single, 

 linear-lanceolate and minutely hairy ; those of the other segments imbricate lengthwise 

 at the sides of the dorsum, and formed of jugate, foliaceous lamellse, oblique at the base 

 and (speaking roughly) cuspidate at the extremity ; in each twin the laminae are unequal 

 in size and rather dissimilar in form, the soialler being obliquely ovate, the larger 

 obliquely subcordate-ovate, with one of the auricles large ; the terminal cusp of both is 

 effectively discontinuous with the major portion of the lamina (through the membrane 

 on each side of its base being deeply incised) and is commonly turned upon its longer 

 axis so as to lie in a plane at right angles with that of the other portion ; the cusps are 

 wider than those of Blasturus, for the most part, and less prolonged. Fangs of the 

 mandibles abrupt ; the brush of the endopodite tapers obliquely to a slender point. 

 Palpus of maxilla i slender; joints 2 and 3, together, slightly longer than joint 1. 

 Lacinise of the 2nd maxillae rather broader, and the lobes of the labium smaller, than 

 those of Blasturns. Tongue produced in the middle into an obtuse emarginate lobe, 

 and prolonged on each side into a slender curved claw-like projection ; paragiossiB acute 

 laterally, rounded in front. Abdomen slender, the hinder lateral angles of the inter- 

 mediate segments shortly and acutely produced. Caudal setae about twice as long as the 

 body. Hind leg a little the longest ; the tarsus nearly J as long as the tibia (the claw 

 excluded). 



Type. Cli. Picteti, Etn. 



Distribution. Europe southwards of Belgium and Saxony ; America (undescribed sp.), 

 Arizona. 



Etymology . yo^oc, and regxw, delighting in the dance. 



The figures of the tracheal branchiae do not display the peculiar trending of the cusps 

 of the laminae, owing to then' having been subjected to pressure, when drawn, in order 

 to exhibit their outline. The species from Arizona is represented by two subimagines in 

 Mr. M'Lachlan's collection. Identification of the nymph was accomplished by dii-ect 

 observation in the field. 



Choboterpes picteti, Etn. Plate XII. 19 (wings, legs, forceps, and penis). 



Potamanthus % maryinatus, Pict., Hist. Nat. Nevropt. ii. Epliem. 208. pi. xxv. 4, 5 (18i3-5) ; Walk., 

 List of Neuropt. in Brit. Mus. part iii. 540 (1858) ; ? Ouliauiue, Neuropt. & Orthopt. of Prov. of Moscow, 

 27(1867). 



LeptophleUa Picteti, Etn., Trans. Ent. Soc. Loncl. (1871), 87; ! if/., op. cit. (1873), 395; ! Rostock, 

 Jahresb. d. Ver. f. Naturk. Zwickau, 1877, p. 84 (1878). 



HabropJilebia Picteti, \ Etn., Ent. Mo. Mag. xvii. 196 (1881) [citation]. 



Clioroterpes [type] limtanica,\ id., op. cit. xvi. 194 (Feb. 1881).—! Cti. Picteti (Etn. MS.), M<^Lacli., 

 Compt.-rend. Soc. Ent. Belg. xxv. 135 (1881). 



SuMmago {Hmny).—\N\n^s, uniformly purplish black. Legs and setae dark piceous; 

 tibiae and tarsi at first reddish piceous. 



Imago {living), d .—Upper portion of eyes intense warm sepia-brown. Thorax jet- 

 black above. Abdomen pitch-black, with pale rufescent joinings ; penultimate ventral 

 segment distinctly, and a few of the segments anterior to it faintly, tinged posteriorly 

 with rufescent ; forceps-limbs rufescent interiorly and distally ; penis and setae pitch- 



