NOTES ON THE COMMON MAYFLY. 



267 



tion, I took some glass tubes filled with spirit to the water's 

 edge, and caught a female in the act of depositing her eggs, and 

 induced her to lay in the tube. These eggs were examined im- 

 mediately on my return home, and I then detected the threads 

 referred to. A few days after I examined the eggs again, and 

 the threads had all disappeared, dissolved by the alcohol. The 

 eggs are provided with some sticky property. Some adhered 

 persistently to the side of the glass tube, and it required a good 

 deal of shaking and rinsing with alcohol to release them from 

 their hold and sink in the liquid. The eggs are bean-shaped, 

 and appear when first laid, and under a one-sixth inch objective, 

 of a greenish colour. This colouring matter dissolves after a time 

 in alcohol, and the eggs are then, as they appear when fresh to 

 the naked eye, white. 



I have never, so far, been fortunate enough to see the 

 actual emergence of the fly from the nymph. Swammerdamm 

 says: — "When the larvae have left their burrows they make 

 their way with all speed to the surface, and the transformation 

 is effected with such rapidity that even the most attentive 

 observer can make out little, except that the winged fly suddenly 

 darts out from the midst of the water." The claspers of the 

 male fly are shaped like pincers, and somewhat resemble those 

 of an earwig. In the female they appear, under a powerful lens, 

 like minute hooks. 



"Is the Mayfly disappearing?" is a question that has been 

 mooted lately. In the 1 Fishing Gazette ' for May 22nd is the 

 following : — " There is no doubt that the Mayfly and many other 

 water-flies have become extinct on many rivers ; they seem to 

 die out first in the upper parts, and gradually appear only lower 

 and lower down. The clearing away of sedges, shrubs, bushes, 

 and trees from the banks and neighbourhood of the rivers 

 exposes the flies more to the exterminating influence of birds, 

 wind, and weather, as well as by removing the natural shelter 

 necessary for nuptial congress. For this reason I do not believe 

 it is reasonable to expect any transplanting of the fly to be 

 successful unless there is plenty of natural shelter. ... I think 

 that the plan of attempting to stock by transplanting larvae 

 offers the best chance of success." 



The Surrey Trout Farm at Haslemere make it part of their 



