TIJE DAY FLY. 
477 
Same naturalifts have pretended, that thefe eggs were all 
impregnated, like thole of fillies, bj a kind of fpernj 
ejected from the body of the males. This opinion, how- 
ever, is combated by Reaumur *, as being attended with 
many difficulties. That natural! it. by the help of a light- 
ed torch, has examined thefe animals narrowly in their 
winged Hate ; and although that method of furveying 
infefts, whole numbers occafion fo much confulion, be 
uncertain, he allerts, that he obferved them engaged in 
liiort copulations ; an affertion the more probable, fince, 
if the ephemeral copulate, that ad behoved to be more 
inftantaneous than in any other race of beings. 
Another fpecies of the day fly is feen to cafl a fkin, 
even after it has arrived at its winged flate : Thus, how- 
ever {lender their wings might at firtt appear, they mult, 
as well as the whole body, have been enveloped in a coat 
which the animal then drops f. 
The ephemera vulgata, or common day lly, is the 
larged of thefe infefts with which naturalilts are yet ac- 
quainted ; it carries at the extremity of the abdomen 
three brown threads, nearly of equal length with the 
body, which is all over brown. The wings are orna- 
mented with brown veins, which form a net-work. 
In Carniole, a province of Germany, this fpecies is fo 
numerous, that the peafants think they make a bad har- 
veft of them, if they do not unload upon their land many 
carts filled with thefe inl'c&s. They make excellent ma- 
nure ; but the number of animals of fo lmall a fiz.e necef- 
fary to fupply the quantity, mull exceed the power of 
imagination to conceive. 
f Vide Eiblia Natuire. f Reaumur, Tome VI. Pref, 
