British Ephemeridce. 3 



This differs from C. luteolum in having no point pro- 

 jecting from the last segment in the middle, just above 

 the base of the forceps ; the terminal joints of the legs of 

 the forceps are comparatively smaller, pyriform with a 

 narrower neck, and are slightly incurved (not straight). 

 The posterior wing also is ligulate, with the apex ellip- 

 tical (not acute or acuminate) . 



Length of body, S 8-9, ? 8 ; fore-wing, c? ? 8 ; set. 

 $ 14-17, ? 11 mm. About twice as large as G. luteolum. 



Hah. — The Manifold, Ham, Derbyshire ; and Grazely 

 near Reading. August to October. 



4. Baetis scambus, n. sp. 



S . Turbinate eyes clove- coloured. Thorax black or 

 piceous above. Legs cretaceous or greenish-gray; the 

 foi-emost tarsi fumose ; hinder tibige and tarsi greenish- 

 white, with slightly darker joinings and claws. Abdomen 

 fuscous, belted with white or greenish-white. Setee 

 white. Forceps rather like those of B. bioculatus ; but 

 their limbs are more slender, and their bases closer 

 together. 



? . Eyes dark olivaceous. Body olivaceo-fuscous. 

 Legs olivaceous, with dark fumose tibiae and tarsi. Setse 

 fumose, with slightly darker joinings. 



The hind-wings are very similar to those o? B. biocula- 

 tus, having the first and the second longitudinal nervures 

 undivided ; but there is no trace of the third nei'vure. 



Length of body, c? 6, $ 6'5 ; fore-wing, c? 6, ? 7 ; 

 set. ^ 12, 9 9-10 mm. 



Hab. — The Dove and Henmoor Brook, near Ashbourne, 

 Derbyshire. June and September. 



The specific name is taken from the crooked legs of 

 the forceps. 



The next four species are not easily distinguished, with- 

 out figures, from B. Ehodani, Pict., which has turbinate 

 eyes more or less sooty; thorax black above, polished ; 

 abdomen more or less fuscous, not belted with white, but 

 sometimes slightly paler in the middle than at the tip ; 

 femora somewhat olivaceous or greenish-gray ; hind- 

 wing oblong, oblique at the base, obtuse at the tip, with 

 a short costal process, the first two longitudinal nervures 

 undivided, the third shorter than the others and also 



B 2 



