38 MEMOIR OF SWAMMERDAM. 



then are tlie most innocent, perhaps, of all others, 

 they are more cruelly treated or used, than the most 

 mischievous of wild beasts. 



" As the ephemerus abounds with useful lessons 

 and moral precepts, so it affords sufficient matter for 

 various speculations. It is engendered, grows to its 

 bigness, and then generates, lays eggs, casts its sperm, 

 grows old, and dies in the space of five hours. This 

 short space comprehends 4ne morning, noon, and 

 evening of its life."* 



The species on which Swammerdam made his ob- 

 servations is the largest known, and is the Ephemera 

 longicauda of Olivier (Encydop. Method. Art. Ephe- 

 mera.) In honour of the individual who made us so 

 accurately acquainted with its history, Latreille subse- 

 quently named it E. Swammerdiana. It is not a 

 native of this country, but occurs in the larger rivers 

 of Holland, Germany, and France. 



About the same time, he investigated in a similar 

 manner the history and anatomy of what he names 

 the asilus or gad-fly, but which is a dipterous species 

 of the modern genus Stratiomys, or chamseleon fly. 

 His attention had been probably attracted to this 

 insect, by the singular breathing apparatus of the 

 larva, which consists of an anal orifice surrounded 

 by a circle of diverging rays of beautifully feathered 

 plumes. This singular structure, and the elegant 

 appearance of the respiratory appendage, has caused 

 it to be often described and delineated in modern 



"Book of Nature, Hill's ed. where will be found a synopsis 

 of the Vita JEphemeri. 



