137 



species is quite unimportant, as all insects are 

 equally welcome, though the larger they are, 

 as in the case of grasshoppers, so much the 

 better, because they then furnish a better 

 mouthful." First, as to species. The dun- 

 drake, or March-brown, is of the genus baetis, 

 and appears, according to the locality of rivers, 

 earlier or later in them, in the month of 

 March. As soon as it appears, it is eagerly 

 devoured by trout. In about four days it 

 becomes the great red-spinner, that is, another 

 species of the dun-drake, which continues 

 on the water longer than the latter fly. Before 

 the dun-drake appears, no fish will take the 

 red-spinner, and generally when the longer- 

 lived latter fly is taken, the dun-drake is 

 refused. Here fish make a striking distinc- 

 tion between species ; and in proving that they 

 do, we also prove how necessary it is to 

 imitate them artificially. Moreover, they are 

 of the same size, but their colour is widely 

 different; consequently, different coloured mate- 

 rials must be used in dressing them. Secondly, 

 as to the assertion, that all insects are equally 

 welcome ; is the common hive-bee at any time 

 equally welcome with the May-fly ? And, third- 

 ly, as to size ; is the May-fly at all times equally 

 as welcome to fish as the wren-fly, one con- 

 siderably smaller ? Mr. Rennie cannot answer 



