TEMPERATURE AFFECTING RISE 85 



by some initial movement of the pupae towards their 

 next metamorphosis. A few heavy drops of rain 

 are followed or accompanied by a rise ; this rise may 

 be produced by an upward movement of the pupae 

 in response to the meteorological influences at work. 

 Again, certain summer evenings, at about the same 

 hour and for a similar period, generally as the sun sets, 

 will produce a general rise ; this rise, so well known 

 to fishermen, is, as far as I can see, to be accounted for 

 only by the cooler temperature inducing a general 

 change from the pupal to the flying state of certain 

 small water insects. The rise of the pupae to the surface 

 excites the fish, which feed on the swimming insects 

 alone, either as they rise to the surface or after they 

 get there, to the disgust of the fly fisherman. This 

 evening carnival of the trout is invariably accompanied 

 by an enormous hatch of small flying Ephemeridae, 

 probably the ones which escape from the surface of 

 the water to which they have risen. Again and again 

 have I witnessed the water at such times fairly boiling 

 with the rising fish, but it has been seldom that I have 

 been successful in landing even as much as a brace 

 of fish, though after this excitement has subsided, 

 my Coachman, Silver Sedge, etc., have proved most 

 deadly. 



I am inclined to think that bulging may be 

 produced by a similar cause that is, by the activity 

 of the sub-aqueous entomological life. 



The method by which the latest food taken by a 

 trout can be determined is by holding the trout in 



