THE DRY-FLY MAN'S HANDBOOK 



legs. 



Fig. 40. Baetis Nymph x 6 



year. The type of the Ephemeridae of this division 

 is the march brown, and Fig. 39 gives a very good 

 notion of the appearance of one of these flat nymphs. 

 The organization of the swimming nymphs differs 

 greatly from the preceding 

 Swimming nymphs. types. They are long, cylin- 



drical in form, and have feeble 

 Perhaps the most remarkable and unmistakable 

 feature about them is the 

 close fringe of strong hairs 

 placed horizontally on both 

 sides of each of the three 

 caudal setae. They prefer 

 water of only moderate 

 pace, and are ever plentiful 

 in the weeds of a chalk- 

 stream which is free from 

 pollution. Their duration 

 of life is generally believed 

 by modern entomologists 

 in some species to extend 

 to one year, and in others 

 they are credited with pro- 

 ducing two broods in the 

 year. Thus in these species 

 the nymphs hatched in 

 the spring arrive at ma- 

 turity and oviposit in the 

 again 



miagmes 



autumn, and the eggs of these 



hatch out in the following spring. Fig. 40 shows a 



