30 THE PALE WATERY DUNS 



Pale watery 

 dun and 

 pale watery 

 spinner. 



Family 

 Genus 



Species 



Genus 



Species 



EPHEMERID^ 



Baetis 



( binoculatus 

 \ scambus 



Ceniroptilum 

 c lutecium 

 \ pennulatum 



PLATE III 



Pale watery dun is a name given indiscri- 

 minately to the small pale species of both 

 Baetis and Centroptilum, 

 and as with the olive dun 

 the distinctions are not 

 very apparent without 

 calling in the aid of the 

 magnifying glass. 



The Baetis species pas- 

 sing under this name are 

 binoculatus and scambus, 

 and, as is common to the 

 Baetis group, the hind 

 wings are comparatively 

 broad (Fig. 5). 



The Centroptilum species 

 are luteolum and pennul- 

 atum. In the former the 

 hind wings are acute at the 

 tips; in the latter these 

 wings are rounded, but 

 not so broad as in Baetis 



FIG. 5. Hind wing of 

 Baetis binoculatus, 

 Pale watery spinner. 



FIG. 6. Hind wing of 



Centroptilum luteolum, 



Pale watery spinner. 



FlG. 7. Hind wing of 



Centroptilum pennulatum 



Pale watery spinner. 



(Figs. 6, 7). The adult forms, the spinners, vary 

 in the colour of the turbinate eyes of the males 



