108 THE SCIENTIFIC ANGLER. 



bed, and burst their " swathings. " They then cast their 

 skins, like stripping off a garment, and reappear as spin- 

 ners. They live about five days in this, the concluding 

 period of their life. We have several times taken for 

 experimental purposes a number of Common Red Spin- 

 ners, Jenny Spinners, and Great Eed Spinners (trans- 

 formations of the Olive Dun, Iron Blue Dun, and Up- 

 winged Browns). These we have deposited upon the 

 water contained in a fish-hatching box, through which 

 ran constantly a stream of fresh water, the whole being 

 well and closely-fitted over. There they have deposited 

 their eggs, each fly dropping several as it rose and fell 

 upon the top of the water. After this last and most 

 important function of their life had been performed, 

 each having deposited its hundreds of eggs, every sign of 

 vitality vanished, and they appeared lifeless, and merely 

 a flimsy form inflated with air. 



By the aid of a powerful microscope we were enabled 

 to investigate minutely, from time to time, several points 

 of special interest to us. By careful and oft-repeated 

 researches we ascertained that from thirty-six to forty 

 days serve to hatch the eggs, when deposited in the sum- 

 mer months, but much longer if in spring ; and almost 

 immediately after this has happened, the larva or grub 

 secretes itself amongst the sediment at the bottom of the 

 water, instinct, doubtless, prompting this as security 

 against the numerous enemies which prey upon it. The 

 form of the larva is shown to be elongated, with six per- 

 fect legs, and whisked tail, also armed with a pair of 

 formidable forceps, with which its food is seized. Along 

 the sides there is a range of web-like appendages, which 

 serve as fins ; and by the aid of this propelling power 

 the larva becomes exceedingly active. In the course of 

 five or six months the larva changes into a pupa, or 

 nympha, by breaking through a filament or outward 

 skin. Upon the shoulders there are now two small pro- 



