T 3*9 3 
Paper formerly emitted. 
IX. Some Obfervations on a fort of Libel I a * 
or Ephemeron, by Mr. Peter Colliiifofl,- 
F. R. S. 
Winchefter , June -23. 1.744, 
Read Jan. 3 i. A $ { walked by the River’s Side at Win* 
XfjL cheftwy I- was told, that how was the 
Time of Year that the May Flies, a Species of Li- 
kella , came up out of the Waters, and were fecn for 
a few Days, and then disappeared. This excited my 
Curiofity, having never fecn this luffed. 
May 2 6, 17440 I was firft fhewn it by the Name of 
May Fly, on account of its annual Appearance in that 
Month. It lies all the Year (but a few Days) in the 
Bottom or Sides of the River, near the Likenefs of 
the Nymph of the fmall common Libellas 5 but 
when it is mature, it rifes up to the Surface of the 
Water, and fplits open its Cafe; then, with great 
Agility, up fprings the new Animal, with a {lender 
Body, with four blackifh-vein’d tranfparent fhining 
Wings,, with four black Spots in the upper Wings; 
the under Wings much fmaller than the upper ones, 
with three long Hairs in its Tail. See Tab. Ik 
Fig. 2. & c> 
The 
* I take this to be the Mufca tripilis mention’d in Moufet , In fed, 
Theat. p » 64. and may properly be called Mufca y Libelles affinis, 
cauda tripili, C, M* 
T t a 
