I 33 2 ] 
1 obfcrvccl this Species of Libella abounded mo 3: 
•with Females j which was very ncceflfary, confider- 
ing the many Enemies they have in their fhort Ap- 
pearance j for both Birds and Fifh are very fond of 
them, arid, no doubt, under the Water arc a Food 
for final! aquatic Infefls. 
What is further remarkable in this furprifing Crea- 
ture is, that, in a Life of three or four Days, it eats 
nothing, feems to have no Apparatus for that Pur- 
pofc, but brings up with it out of the Water fuf- 
ficient Support to enable it to fhed its Skin, and 
perform the principal Ends of Life with great 
Vivacity. 
They appear at Six o’ Clock in the Evening. On 
the 26th of May I perceived a few j but the 27th, 
28th, 29th, and 30th, it was a Sight very furprifing 
and entertaining, to fee the Rivers teaming with in- 
numerable pretty nimble flying Animals, and almoft 
every thing near cover’d with them $ when I looked 
up, the Air was full of them, as high as I could dif- 
ccrn$ and feem’d fo thick, and always in Motion, 
the like it feems when one looks up and fees the 
Snow cotning down : And yet this wonderful Ap- 
pearance, in three or four Days after the laft of May? 
totally difappear’d. 
After I had drawn up thefe Obfervations, it was 
more than a Year before I had the Pleafure of 
perufing Mr. Reaumur s elaborate Work, wherein 
he deferibes this Infedt by the Name of Ephemere 
Tome vi. p. 516. PI . 44. 5 but, as I find we vary 
in many Particulars, and as it may tend further to 
7 illuftratc 
