CH. IV.] "LIGHT FLY FOR LIGHTNESS :" QU. ? 57 



converse to hold good during the day. There 

 are, however, doubtless occasional exceptions, such 

 for instance as the yellow cow-dung fly, which I 

 have found a great killer on a stormy day, par- 

 ticularly among meadows, where the natural fly 

 would abound, and when it would be swept off 

 upon the water. 



On " stickles " (the expressive Devonshire word 

 for the broken water at the head of pools) I think 

 I have generally found a small bright fly (yellow 

 floss-silk body and starling wing, for instance) 

 kill better than a larger sombre one, but the 

 latter to answer better in the still dark pools. 

 This, which I have noticed quite independently of 

 the last theory, certainly tends to support it, as 

 Trout, in common with most fresh-water fish, un- 

 doubtedly lie upon the shallows when the weather 

 is bright and hot, and retire to the deeper water 

 as it becomes cold and gloomy. It is for the 

 same reason, as I believe, that Trout do not, in hot 

 weather, so much affect those parts of a river 

 which are densely wooded, and consequently shad- 

 ed, as those which lie open and exposed to the 

 sun. A red fly I have always found kill better 

 rather late in the evening than at any other time 

 of the day. In the white-moth tribe, as night-flies, 



