258 INSECT WATER TRESPASSERS. 



are familiar to all students of science. One such 

 instance occurred to myself. I had settled a doubtful 

 point in the anatomy of insects by dissection of the 

 humble bee. According to custom, the description of 

 dissection was written in full, and entered in the book. 

 Some six months afterwards, the same discovery was 

 made in France, and published. But as, in all matters 

 of science, the individual who publishes the discovery 

 first has the credit of it, this particular one belonged 

 to France, and not to England. 



The following account of the discovery of the 

 Swimming Ichneumon was read before the Linnaean 

 Society on May 7, 1863, and afterwards printed in the 

 " Transactions " of that Society. 



" On one of the early days in August, I was enjoy- 

 ing myself by watching the animals in a basin of pond 

 wnter. 



" It is customary to regard the inhabitants of 

 fresh water as less beautiful and varied than those of 

 the sea. But though our inland lakes and rivers can 

 boast no sea anemones, no starfishes, medusae, shrimps, 

 nor sea urchins, they still are full of beauty and 

 variety. 



1 ' Without counting the rarer forms, almost every 

 weedy pool contains specimens of daphnia, cy clops, 

 diaptomus, and asellus among Crustacea, the hydra 

 among polypes, the lovely green volvox, and many 

 other alg89, besides numerous desmidiae and diato- 

 macese, with insects almost innumerable. Besides the 

 perfect insects, such as water beetles, notonecta., nepa, 

 and other hemiptera, there are larvae of dragon flies, 

 beetles, phryganeas, and ephemeras, the beautifully 



