32 [July, 



31. Bhithrogena semicolorata, Curtis : Eevis., 236 and 256, pi. xxiv, 



43, 43e [adult details], and pi. liv (part) [nymph] (1884 and 



1885), = Heptagenia semicolorata, Cat., p. 10 ; Mon., 136 (in-. 



eluding semitincta, Pict.), pi. vi, 9 [genitalia]. 



In addition to the discoloration of the basal portion of the wings, usually 



noticeable, the $ of this species can be identified by the narrow, flattened genital 



stimuli, abrupt and minutely denticulate at the tip, and closely appressed to each 



lobe of the penis. 



Streams and rivers. Summer and autumn. 



32. Heptagenia sulphurea, Miiller : Eevis., 236 and 268, pi. xxiv, 45 



[legs and penis] (1884 and 1885), = H elegans, Cat., p. 10 ; 

 Mon., 145, pi. iii, 5, and vi, 18, ISb [adult details]. 

 Metathorax spotless at the sides. Femora not banded. Very similar to S. 

 flavipennis in other respects. Defective specimens of Potamanthus luteus, especially 

 if in sub-imago, are liable to be classed with Septagenia in collections. Neither of 

 our British species has the dark longitudinal dorsal stripe on the abdomen noticeable 

 in allied continental species. The nymph of Septagenia is figured in Eevis., pi. lx. 



Summer and autumn. Rivers and streams. 



33. Heptagenia flavipennis, Dufour : Mon., 144, pi. vi, 17, 17c [adult 



details] ; Eevis., 273 (1885), = Baetis longicauda, Stephens, 

 Cat., p. 11 [excl. B. subfusca, Steph.]. 

 Fore femur more or less faintly dark-banded in the middle. Metathorax with 

 a small rounded black spot on each side behind the upper part of the leg socket. 



Summer. Eivers. Near Eeading. 



34. Ecdyurus venosus, Eabricius : Eevis., 236 and 283, pis. xxiii and 



xxiv, 46 [adult details], and lxii [nymph] (1884, 5, and 7),= 

 Heptagenia venosa, Cat., p. 11 ; Mon., 151, pi. vi, 24 [genitalia], 

 = H. longicauda (not of Steph.), Cat., p. 11 ; Mon., 152, pi. vi, 

 25 [genitalia], = Baetis subfusca, Stephens, Cat., p. 11 [in 

 synon.], = B. niontana, Hag., Ent. Ann. (1863), p. 26. 

 Foro femur uniformly pitch-brown, excepting just at the base. The impressed 

 ventral dots and dashes are usually colourless. Pterostigmatic region of the fore- 

 wing usually obscured, sometimes clear. A browner species than the next. 



Streams and rivers. Summer and autumn. 



35. Ecdyurus insignis, Eaton : Eevis., 2S8, pi. xxiv, 46</ [penis from 



above], = Heptagenia insignis, Cat., p. 11 ; Mon., 153 (excl. 



Baetis niontana, Hag.), pi. vi, 26, 2Gb [genitalia and ventral 



markings]. 



Fore femur uniformly pitch-brown. The impressed ventral dots and dashes in 



segments ono to seven of the abdomen are black. In the pterostigmatic region of 



