300 EEV. A. E. EATOX OX EECEXT EPHEMEEID.li OR MAYFLIES. 



Length of body 6-5-S-5 ; setae, d im. 19-22, subim. 12-13, $ im. 18-22, subim. 

 15-18 mm. 



ITab. Eock Island, 111. [After AValsh.] 



Heptagexia simplex, Walsh. 



Heptagenia simplex, Walsh, Proc. Eut. Soc. Philad. ii. 204 (1863) ; Etti., Trans. Er.t. Soc. Loiulou 

 (1871) 111. 



Suhimago. — Wings and neuration yellowish. 



Ima(jo {iking), 6 . — Fore tarsus f as long as the tibia : joints 1-3 of the t;irsus sub- 

 equal to each other ; joint 4 a little shorter. Eyes bright greenish yellow. Notuui 

 flesh-colour. Abdomen in segments 2-7 hyaline; segments 8-10 whitish ; forceps white ; 

 setae white, tinged with dusky at the extreme tip. Pemora yellow or yellowish ; tibiae 

 and tarsi Avhite, with the extremities of the tarsi, the tip of the fore tibia, and sometimes 

 the joinings of the fore tarsus fuscous. Wings hyaline ; neuration colourless, excepting 

 in the distal \ or f of the fore wing, where it is fuscous, and sometimes the cross-veiulets 

 of the marginal area of the same wing are also fuscous ; in the pterostigmatic region the 

 cross-veinlets are coarse. 



$ . — Fore tarsus h as long as the tibia ; joint 1 as long as joint 2. Abdomen egg- 

 yellow. Setae scarcely tinged with dusky at the tip. Only the extremities of the tarsi 

 are a little tinged with fuscous. Wing-nenration colourless, excepting that a few cross- 

 veinlets towards the extremity of the costa are dusky, and that the costa, subcosta, 

 cubitus, and radius are tinged with yellowish. Length of body, d 6-8, $ 7-8'5 ; setae, 

 d im. 14-18-5, subim. 10"5, $ im. 14-16, subim. 10-15 ; expanse of wings, d 16-20*5, 

 2 19-25-5 mm. 



Mab. Eock Island, III., June. [After Walsh.] 



Heptagenia critextata, Walsh. 



Heptagenia cruentata, Walsh, Proc. Ent. Soc. Philad. ii. 205 (1863) ; Etn., Trans. Ent. Soc. London 

 (1871)140. 



Sitbhnago. — Wings and their neuration dull opaque yellowish. Setae tinged with 

 dusky ; their joinings fuscous, less distinct than in the imago. 



Imago {living), d . — Yellowish. Fore tarsus as long as the tibia; the first joint much 

 shorter than the second. In the hinder tarsi joint 1 is slightly shorter than joint 2. 

 Eyes jjale bluish grey, intersected by a black line. Notum and dorsum sanguineous. 

 Seta.^ whitish, with fuscous joinings, which towards the base are alternately broad and 

 narrow. Forceps i:)ale, fuscous towards the tips. In every leg the distal half of the 

 femur, the basal f and the terminal j of the tibia are pale sanguineous, that portion of 

 the femur presenting at each extremity a narrow dark sanguineous annulus, and the 

 tarsus has dusky joinings and ungues. Wings hyaline, tinged uniformly with yellowish 

 along the costa ; neuration close to the Aving-roots hyaline, but elsewhere fuscous, 

 excepting the costa, which is tinged with yellow in its basal § : the bulla of the " 2ud 

 costal vinn " [? subcosta] for about 0'5 mm. is thickened and obfuscated. 



2 • — Fore tarsus shorter than the tibia ; joint 1 shorter than joint 2, and slightly so in 



