ANCIENT ANGLING AUTHORS 213 



on. I had the pleasure to shew my Friends one that 

 I held on my Finger during the time it perform'd 

 this great work. It was surprising to see how easily 

 the back part of the Fly split open and produced the 

 new Birth, which I could not perceive to partake of 

 anything from its Parent, but leaves Head, Body, 

 Wings, Legs, and even its three hair'd Tail behind 

 on the Case. After it has reposed itself a while it 

 Flyes with great briskness to seek its Mate. In the 

 new Fly a remarkable difference is seen in their 

 Sexes, which I could not so easily perceive in their 

 first State, the Male and Female being then much 

 of a size, but now the Male was much the smallest, 

 and the Hairs in his Tail much the longest. I was 

 very careful to see if I could find them engendering, 

 but all that I could discover was that the Males 

 separated and kept under the cover of the Trees, 

 remote from the River. Hither the Females resorted 

 and mixed with them in their flight (great Numbers 

 together) with a very brisk motion of darting or 

 striking at one another when they met with great 

 Vigour, just as House Flyes do in a Sunny Room : 

 This they continued to do for many Hours, and this 

 seem'd to be their way of Coition, which must be 

 quick and soon perform'd as they are of so short 

 duration. When the Females were impregnated, 

 they left the Company of the Males and sought the 

 River, and kept constantly playing up and down on 

 the Water ; it was very plainly seen every time 

 they darted down they Ejected a Cluster of Eggs, 

 which seemed a pale bluish Speck, like a small drop 

 of Milk, as they descended on the Water ; then by 

 the help of their Tail they spring up again, and 

 descend again ; thus continuing till they have 

 exhausted their stock of Eggs, and spent their 

 Strength, being so weak that they can rise no more 

 but fall a prey to the Fish, but by far the greatest 

 numbers perish on the Waters, which are cover'd 



