106 THE WONDERFUL TROUT 



during part of May, the ' March browns ' are 

 abundant, the large lighter ones corning on a 

 little later than the small darker ones let 

 us say of the same swarm. We give a general 

 preference to the lighter, as we believe the 

 trout do ; and often when the darker males (?) 

 are going down like fleets of herring-boats, 

 the female (?) fly makes the basket. Stewart 

 advocates a smaller imitation than the 

 natural insect. We do not find that advice 

 invariably good. 



Geological conditions : 



A friend who has studied the question of 

 the influences of geological conditions upon 

 trout and trout food, and one who has had 

 abundant and continuous opportunities both 

 as an angler and one of the staff of the 

 Scottish Geological Survey, reports to us as 

 follows : c My impression is, the condition 

 of trout depends almost entirely upon the 

 abundance of fly food ; and as the hatching 

 out of the river flies is mainly dependent on 

 temperatures of air and water, geological condi- 

 tions only indirectly influence condition of the 

 fish/ Mr Hinxman continues : ' The trout 

 in a limestone district are well fed owing to 



