TG Brown ‘Trout 
and soon thereafter return to the main stream, where they remain in the 
deep pools till March, when food is more plentiful. In April, when 
the flies begin to appear—blue duns first, and then March browns— 
they begin to leave the deep pools and come on to the shallow streams, 
where the flies are most abundant. At this time they often run up 
rivers for a considerable distance. In large streams they are generally 
in the best condition about the 15th of May, while in the smaller streams 
they are not in good condition till June; and, strange to say, in the 
south of England, on the Itchen, trout are not in good condition until 

Fic, 163.—3-lb. Loch Crosophuill Trout, Sutherland. June 1900. 
they have had at least a week’s feeding on Mayflies, which is generally 
about the first week of June. 
On nearly all the northern rivers there is an abundance of 
February reds, blue duns, and March browns. The March browns 
are nearly as large as Mayflies, and the trout feeding on them soon 
come into perfect condition. On many of the streams of the south of 
England no March browns appear. This is owing to the sluggish 
nature of the rivers and the want of round boulders in the bottom, of 
which the larvae of the March browns are extremely fond. Their 
thin flat bodies appear to be adapted for whirling round the stones, 
which protect them from their enemies, 
Flies bring trout into condition much quicker than the food they 
obtain on the bottom. A cold, backward season keeps back the 
