Ephemeri vita, or, The natural history and anatomy of the Ephemeron, a fly that lives but five hours written originally in Low-Dutch by Jo. Swammerdam ...
Swammerdam, Jan, 1637-1680., Tyson, Edward, 1650-1708.

CHAP. I.

That the Ephemeron is Produced out of an Egg.

AS all Vegetables proceed from a known Fructi∣fying Seed; so is also the Production of all Animals and Insects, viz. out of a Seed or Egg: So that nothing we discern to have life, but it proceeds from an Egg, Man as well as all other Creatures. And notwithstanding the Common Opinion that many Insects named Exanguious, are chance-births, taking their original from Corruption, that is, out of the motion of the moisture and warmth which proceedeth from Corrupting matter, either in Inanimate or Sensitive Bodies, or Vegetables; constant experience teacheth us the contrary, as, among other, appeareth in this account of the Production of the Ephemeron, which proceedeth from a Visible and Page  2 known Seed, contrary to that false opinion of men prejudiced to the contrary, who believe they are Pro∣duced out of putrifying Clay and Water; as if such a chance-Productor had the power to produce a Creature in all Ages to be admired, and hardly by the most In∣genious and Wise to be described.

This (a)Ephemeron is a Four-winged creature, fur∣nished with Two small Horns, Six Legs, Two very long and straight hairy Tails, and living at longest in this shape or form but Five Hours; is found yearly in all the mouths or entrances of the Rhine, as the Maes, the Wael, the Leck, and the Isel; about Mid-summer flying on the Surface of the water for Three dayes succeeding; but with this difference, that those which have lived and flown the First day, die the same Evening; and the same happens the Second and Third day, and then ceaseth till next Year and Season when the like happens again.

At the same time the (b) Female Ephemeron being risen out of the water, and in the rising, having shed her Skin, and having for some time flown, and as it were sported above the Surface of the water, she shoot∣eth her double (c) Egg cluster, or Ovarium in the water; after which the (d) Male also being risen out of the water, and as before in the rising having shed his skin, and afterwards on Land stript another (e) thin Film, also shooteth his Seed on the Female Seed, and thereby fructifieth it. But how properly this Genera∣tion is effected, and how these Insects rise out of the water, and how in the water and on the land they shed their Skins, shall be in this following relation more largely and circumstantially described.

This very wonderful flight of this Insect, living in this form and shape but Five Hours, I have for the first time seen in a Branch of the Rhine, running by Cui∣lenborch in the Year 1667. I find also in Clutius, who hath writ of these Insects, that they are also found at Arnhem, Zutphen, at the Cut by Vtrecht, at Rot∣terdam,Page  3 and several other places. As also that D. de Mey hath given a particular narration thereof, as may be found at the end of the Historical Observations of Goedaert. And not only in our Age, but in some Ages past mention hath been made of these or the like Insects by the Philosophers, as by Pliny, Aristotle, Aeli∣an, and others, who have made search into the nature of Insects, and by whom this Insect is described under the name of Hemerobius, Ephemerus, and Diaria, as appeareth in their writings; as also in the foremen∣tioned Book of Augerius Clutius, published An. 1634. But what degree of knowledge they have had of this Insect, and what for truth they have recorded thereof, will appear to those who shall take the pains to examine them according to this Treatise.

The Eggs of the Ephemeron being in the foremen∣tioned manner shot in the water, and besprinkled with the Milt or Seed of the Male, they sink gradually, and are by means of the streaming water spread here and there on the clay or ground; as also for that by their shape, which is a (f) flattish round, they are fitted for a spreading in their sinking; and therefore if with the point of a knife you shall let them down lei∣surely in the water, you will find them neatly separate one from the other.

How long these Eggs remain under water unhatch∣ed, or in how many days the tender limbs of the worm are so far grown as to have strength to break through the shell or skin, is very difficult to be declared, not∣withstanding by often digging in the Clay, in search for them, or by keeping some of their Eggs in a vessel with Water and Clay, some knowledge thereof might be attained. It shall suffice for the present to say, that the Egg of the Ephemeron produceth a Six-legged Worm, which the Seamen and Fishermen name Dever Aas, or Shore-baite, as hereafter shall be mentioned.