246 THE DRY-FLY MAN'S HANDBOOK 



old red spinner so well known to the fly-fisherman. 

 Plate XIX shows this insect. 



The name pale watery dun is applied by fishermen 



to four natural insects, two 



Pale watery duns. species of the genus Baetis — 



B. binoculatus and B. scambus; 

 and two of the genus Centroptilum — C. luteolum and 

 C. pennulatum. They are so similar in appearance 

 Fig. 44 that for all practical angling pur- 



poses they may be taken as iden- 

 tical. It is, however, quite easy 

 X 3° to differentiate them by the shape 



of the hind wings. The hind wings of B. binoculatus 

 are as shown in Fig. 44, and the hind wings' of 

 C. luteolum and C. pennulatum are given in Figs. 45 

 and 46 respectively. The angler will never forget the 



Fig. 45 ff Fig. 46 



X 30 X 30 



difference in shape between the hind wings of Centrop- 

 tilum and Baetis if he will just consider that the deriva- 

 tion of the word Centroptilum is from the Greek Kevrpov, 

 a spur, and tttlXov, a wing. He can distinguish the olive 

 dun from Baetis binoculatus by the nervure of the hind 

 wing, and also by the fact that the pale watery is a much 

 smaller and generally paler coloured insect than the olive 

 dun. Plate XX shows a female pale watery dun, B. bino- 

 culatus. Nos. 14 and 15 in the new set of patterns are 

 the male and female pale watery dun respectively. 



