26 £ July ' 



long as the second, and rather stouter than it. Lateral lobes of the 

 tongue broadly claw-shaped, with the points turned outwards, narrower 

 than the median lobe. Three caudal setae. Pictet, Mon. Ephem., pi. 

 16, f . 1 — 7, may be an Ecdyurus, but, if so, are apparently not accurate 

 in minutiae. Type, E. venosus, Fab. Distrib., Europe andN. America. 



Epeorus, n. g. 



Imago. Hind tibia of J about twice and a half as long as the 

 tarsus (in Colorado species twice and one-fifth), whose proximal joint 

 is almost one-twelfth as long as the tibia (Colorado one-eleventh). 

 Fore-tarsus in £ about once and one-sixth (Colorado nearly once and a 

 half), in ? nearly three-quarters as long as the tibia. Relative lengths 

 of the tarsal joints: — fore-foot, g, 18, 18, 15, 13, and 9 (Colorado, 

 32, 32, 32, 23, 10); ? , 7'5, 8, 7'5, 5, and 8 ; hind-foot, <J, 45, 4'5, 35, 

 2, and 6 (Colorado, 45, 4"5, 45, 3, and 7). Caudal setae two, in <$ 

 about twice and three-quarters, in $ twice, as long as the body. Penis 

 lobes of moderate breadth, divergent. 



Wings of sub-imago greyish, or sometimes yellowish, with dark 

 neuration, but with neither fasciae nor streaks. 



Nymph with seven pairs of lateral tracheal branchiae on the 

 abdomen, the fibrils scanty, not half as long as the lamina, to whose 

 edge they stand at right angles ; the laminae decumbent, with a sub- 

 median trachea rather irregularly branched. Head rounded, flattened. 

 Labrum distinct, small. Mandibles terminated by a pair of short 

 broad teeth, the outermost less than half as long as the space between 

 the base of the other and the point of the molar tuberosity. First 

 joint of the upper maxillary palpus almost two-thirds as long as the 

 second, rather stouter than it, and slightly dilated. Lateral lobes of 

 the tongue relatively large, oblong. Median seta absent in the adoles- 

 cent insect. Hind edge of pronotum straight. Type, E. torrentium, 

 n. sp. Distrib., Portugal, the Pyrenees, the Alps, and, perhaps, also 

 Oregon, Colorado and Costa Rica. [The American species have, per- 

 haps, rather slenderer legs than the European.] 



Epeorus torrentium, n. sp. 

 Imago (living), <$. Oculi above dark fuscescent, darker beneath. Thorax 

 lutescent above. Abdomen above, fusco-luteous, paler at the sides, with oblique 

 piceous streaks from the dark tips of the segments ; the usual pale dorsal spots very 

 distinct from the second to the eighth segment ; beneath, with a dark ventral stripe 

 enlarged posteriorly in each segment, and containing four darker lines. Neuration 

 of wings black. Fore-legs piceous, or luteo-piceous, the tarsal joinings paler, the 

 ungues alike and sub-equal ; hinder legs gamboge-yellow, with the usual bands 

 indistinct, the tarsi blackish, with darker claws and joinings. Setae fuliginose, darker 

 at the base, with dark joinings. 



