36 REV. A. E. EATON ON EECENT EPHEMEEID.E OE MAYFLIES. 



Aperture of the anterior thoracic spiracle oblong, with a salient rounded drooping valve at 

 its upper border ; that of the posterior spiracle round. Setfe 3, in ? subequal, glabrous, 

 about J as long as the body. Hinder lateral angles of the intermediate abdominal 

 segments acute, but seemingly not prolonged into projections ; 9th ventral segment not 

 prolonged into a lobe behind, nor cleft, but entire. 



Distribution. Central America. 



Type. a. Salvinics. 



Mymology, Ofioioc and vev^iov, from the mutual likeness of the wing-nervures. 



HoMOEONEUBiA Salvini^, Etu. PI. III. 6 (wings, ? ). 



HomcEoneuria [type] Salvinim\ Etu., Ent. Mo. Mag. xvii. 192 (1881). 



Imago {dried), 2 . — Head and thorax pitch-black above ; abdomen dark warm sepia- 

 brown above, with the joinings either transparently whitish or opaque sepia-brown, 

 according as this region is distended or not ; belly warm sepia-grey, with the hindermost 

 3 or 4 segments warm sepia-brown; sette pitch-black. Legs concolorous with the 

 venter ; the fore legs darker than the hinder. Wings transparent, faintly smoky, with a 

 glowing purplish French ultra-blue reflection, changing (in a very oblique front view) to 

 very light purple-madder bronze ; neuration opaque, coloured and bordered narrowly 

 with very light bistre-brown. Length of l)ody, ? , 8-11 ; wing 8-12 ; setse 2-5-3-5 mm. 



Hah. Guatemala ; Duenas, 4950 ft., and Accytuno, 5100 ft. alt. (Salvin, in M-^Lach. 

 Mus.). The specimens were secured early in the morning while floating dead upon the 

 surface of the stream, when the flash of the wings was very conspicuous. In some 

 examples, the thinner portions of the integument in the Iiinder parts of the notum are 

 whitish. . 



Section 2 of the Genus, Type of Polymitai-cys. AdiM. — Subcosta of the fore wing 

 displayed (except in dried Campsurus, 2 ). Posterior margin of 9th ventral segment in 

 2 not extended into a lobe. Pronotum tumid ; its hinder border straight (excepting 

 perhaps in Jolia, c? , it may be sinuous behind). 



Nymph fossorial or predatory ; in those that are known, the median lobe of the tongue 

 is obtuse. 



EUTHYPLOCIA, Etn. 1871. 



Illustrations. Adult (details), PI. IV. Nymph (whole figure and details), PL XXIX., 

 see alsoPict., Hist. Nat. Nevropt. ii. Eph(^m. PL XV. 2-1 [with circumspection]. 



j^clult. — Discal cellules of the fore wing large, and in the vicinage of the terminal and 

 inner margins transversely elongated, especially those posterior to the sinuous anal 

 nervure, which are themselves sinuous. <s , fore leg about as long as the head and body 

 together : the tarsus longer than the femur, which is about f as long as the tibia. Tarsal 

 ungues equal and nearly alike. Aperture of the anterior thoracic spiracle elongate, or 

 oval, in the dried insect, with an arched upper valve ; that of the posterior spiracle 

 narrow, elongate and gaping. Setse 3, subequal, about 3f as long as the body in the 6 ; 

 in ? glabrous, but in c^ sparsely pubescent beyond the middle. ^ , eyes of moderate 

 proportions, mutually remote ; anterior ocellus the smallest. Porceps-limbs inserted at 



