38 
MEMOIR OF SWAMMERDAM. 
tlien are the 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 the 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 ( Encyclop . 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 chamasleon 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 Ephemeri. 
