100 EEV. A. E. EATON ON RECENT EPHEMERID^ OE MAYFLIES, 



pitch-brown, with joinings 2-7 opaque ; venter probably lighter than the dorsum, and 

 more of a warm sepia-brown. Setas warm sepia-brown. Legs pitch-brown, the fore tarsus 

 and the hinder legs rather lighter than the fore femur. Wings vitreous, with a faint 

 brownish grey tint; their neuration, in opaque view pitch-brown, transmits a brown 

 amber-colour ; the marginal area of the fore wing contains 3-7 indistinct cross veinlets 

 before the bulla, and 11-14, mostly well defined, beyond it, those in the pterostigmatic 

 region are simple and usually slightly curved. The form of the genitalia is noteworthy. 

 Length of body 5, wing 5-6 mm. 



Hab. Dedham, Mass. (M'^Lach. Mus.). The apparent presence of a short joint next to 

 the basis in the forceps-limbs is the sole cause of my hesitation in ranking this species in 

 Leptophlebia. 



I have seen specimens of several other North- American species of Leptophlehia, but not 

 sufficient for their description. 



BLASTURUS, Etn. 1881. 



Illustrations. Adult (details) PL XL 18. Ni/mph PI. XXXIIL, see also {?)B. ves- 

 pertinus, L., below. 



Adult. — Similar to Lep)topldebia in the form and neuration of the wings, the structure 

 of the mesothoracic spiracle, the 3 genitalia (in the known species conformable to those 

 of L. niarginata), the ventral lobe of the 9th $ abdominal segment, the legs, and the 

 ungues of the tarsi ; differing from that genus in the proportional lengths of the caudal 

 setie, which vary with the species. Median seta considerably shorter than the others ; 

 outer seta; in d 2-3 times as long as the body, median from f-1 the length of the body ; 

 outer setse in $ l^-lf, median \—^ as long as the body. 



Nymj)h (judging from its structure) latent ; abdominal tracheal branchiae diversiform, 

 foliaceous and fringeless ; those of segment 1 bifid, with minutely hairy linear-lanceo- 

 late divisions ; those of the other 6 pairs reclinate upon the sides of the dorsum, 

 and formed of jugate, obliquely subovate, tail-pointed lamellae, whose cusps are minutely 

 hairy at the edges, and are traversed longitudinally by the main tracheai of the lamellae. 

 The following slight diff'erences are noticeable in the outlines of these lamellae : — in those 

 of segments 2-6 the outer division of the twin lamella, at the base of the cusp, is incised 

 on one side and has a sinus on the other side, while the inner division is incised on both 

 sides of the cusp ; but in those of segment 7 are no incisions. Caudal setae defective in 

 the specimens examined. Fangs of the mandibles in a large measure similar to those of 

 Leptophlehia', the endopodite slender, somewhat abrupt, and furnished with a slender 

 brush of hair. Palpus of maxilla i. slender ; tlie last 2 joints together constitute little 

 more than half of the whole. Lacinia of maxilla ii. broad, nearly in the form of the 

 quadrant of a circle. Tongue rotundly subquadrate ; paraglossse broadly rounded. 

 Abdomen slightly dilated in the middle ; hinder lateral angles of segments 8 and 9 

 shortly and acutely produced. Hind leg a little the longest ; the tarsus (excluding the 

 claw) ^ as long as the tibia. 



Type. B. cupidus (in Ephemera), Say. 



Distribution. Temperate N. America, and perhaps Scandinavia. 



