VARIED SHADES OF THE IRON BLUE. 22/ 



extremity of the body. In this new dress, the insect 

 after the manner of all other spinners, is prevalent 

 at sunset, whenever the Iron Blue has been well on 

 in the course of the day, which generally is the case 

 on all cloudy days, between April and October, 

 though the colour of this fly changes somewhat during 

 this period. In August the Iron Blue assumes a 

 more olive cast upon the body ; in September and 

 October the precise shade and colour in wing, leg, 

 and body is the same as the Olive Dun of the same 

 period, having a rusty shade upon the body precisely 

 similar, the only difference being in point of size. 

 These little duns are sometimes erroneously supposed 

 to be half-matured Olive Duns ; but flies do not grow 

 or expand gradually, they are full sized when they 

 quit their sheaths, as in the larva and pupa state 

 they feed voraciously, laying up an internal store 

 which lasts them the remainder of their existence, as 

 we have elsewhere observed. The Jenny Spinner is a 

 good killer, even when the water is extremely fine. 

 The Yellow Dun of May is very prevalent on fine 

 days, when it should be on the cast The Alder 

 fly is very abundant from about the last week in May 

 to the middle of June. It is a flat-winged fly, and 

 comes from a water nympha. The wings are of a 

 dull brown, veined, the body being a dark claret, and 

 the legs of a rusty black shade. It is a great favourite 

 with trout and chub, particularly towards evening. 

 The natural insect may be used for dibbing, it being 

 a large fly, though slightly varied in different localities. 

 The Black Gnat is a very small fly, which is a great 



