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. VIII.

In how wonderful a manner the Worm Changeth into the Haft or Ephemeron.

THE time of the Worms Change being come, and their Wings in their (a) Cases, having attain∣ed their full stiffness and Colour, and that the Worm is forced as it were naturally to a Change; all the Worms thus fitted and prepared, leave their Cells, be∣taking themselves to the water, and out of the water to flight, which commonly hapneth in the Evening Page  30 between the hours of Six and Seven, as I have observed it in the year 1671. the 13th of Iune.

Those other Worms that have not attained that ma∣turity and growth remain yet in their Cells, but those that have quitted their Cells and betaken themselves to the water, make all the speed possible to attain the Surface of the water, which the one attaineth sooner than the other, and then each Worm (a) immediate∣ly changeth into a (b) Winged Creature, which Change or shedding its Skin is so sudden, that by the strictest observation it would be judged that they flew through the water as they are.

All the Insects that I hitherto am acquainted with have a certain time by the God of Nature allowed them, to stretch out their Wings and to dry them be∣fore they betake themselves to flight: and notwith∣standing the conceived King of Bees, like our Worm suddenly leaveth his Cell, yet not before he hath for some time in his Cell spread out his wings and dryed them.

But on the contrary our Haft or Ephemeron is almost in the same Minute a Worm and a Fly, for where you cast your Eye on the Surface of the water, and per∣ceive the water to bubble, you see them as it were flying out of the same.

When in a Boat you lye cross the stream, you may best perceive the bubling of the water, and the rise of the Worm changed into a Flie, out of the water; but how swift soever the hand is in Catching the Worm yet swimming in the water, yet can it not bring it un∣fledg'd to sight; but if you bruise it a little about the Breast you may bring it unfledg'd out of the water, which practice is wholly necessary if you desire to view it unfledg'd and in its Skin.

But how this sudden expansion of the Wings can be effected is strange to consider, for that they have nei∣ther Muscles nor Joints in the midst, being only neat∣ly foulded and pleated together in their cases, and Page  31 which in a very short time must shed another Film, but how 'tis is difficult to answer; for my Concepti∣ons were that these Wings ought to have been furni∣shed in their middle part with Muscles and Joints as we find in other Insects, by which means they very neatly fold up their Wings in a small room, and by means thereof also expand them again; as is chiefly observable in the Ear-worm, or Forfica, which hide very large Wings under a small Shell or Case, as if they had none at all; and like as the Ear-worm by means of Muscles and Joints placed in the midst of its Wings, can fold them in a small compass in manner like the wings in our Worm, and suddenly expand them again: I conceive the same need of like Muscles and Joints in the wings of our Worm, but it hath otherwise pleased the great Creator who is various and wonderful in all his works, and not to be tyed to the same means in effecting the same thing in the one as in the other.

But yet to say something of my own observation in relation to the swift expansion of its Wings, I conceive that the water pressing on all sides, and being warmer on its Surface than in the body thereof, may much assist to this expansion, by reason that the bloud at that time moving from the heart to the wings, to aid or effect that expansion, by the warmth may receive a more vi∣gorous motion; as for instance, when one hath a Vein opened in his foot and holding the same in warm wa∣ter, by the warmth of the water his bloud becometh more briskly moved and runs swifter out. So also while all the bloud and moisture of this Insect when it swimmeth and sheddeth its Skin is briskly moved, the surrounding water may be very assistant to add to the motion of the inclosed moisture, and so cause a more vigorous expansion of the wings: Therefore if at that time their Wings are hurt or cut, they soon bleed to death, or at least the Wings flag and spread no more. And as assistant to the ready▪ spreading out of the wings is also the Air which is conveighed into them by a Page  32 great number of Air-vessels, which may be useful to stiffen them, and cause the moisture to exhale out. If the Wing of the Worm when it is ready for flight be cut off and laid in a small vessel with water, it will im∣mediately spread it self in the same till in a short time it be fully expanded, that it would be ready for flight if it were but dry and stiff. I have several times reite∣rated this Experiment, and thereby learned in what manner they do expand, for being laid, as before, in the water, (a) First the great folds do open, where∣upon (b) the Wing by degrees becometh extended in its length, and then are expanded the (c) long folds of the Wing very wonderfully, till at last the (d) Wing spreads out in its full dimensions as is represented in the (e) Figure of the Insect according to the life, but the representation of the Wing in its folds, and the man∣ner of unfolding was taken by the help of a Micro∣scope. When the Wings are yet in their folds their Colour is a dark Grey, but as they expand they become lighter Coloured.

The manner of the Expansion of the Wings in other Insects is quite different from this last mentioned as in those of the Dragon-flie, or the Libella or Perla, as also the Tipula terrestris or Culex Maximus, and the Locusta or Locust, which Insects have their Wings placed in their Cases in a very crumpled manner, being neither long-wise folded, nor again, Snake-like, as in our Worm, for which reason their Wings are expanded with more trouble, and require more time thereto.

In the Schoen-lapper, the Witkens, or the Capel∣lens (which are some sorts of Butter-flies) is yet another manner in the fold of their Wings, for they are close rumpled together, so that no pleats, folds or rumples appear, and neither having in their middle part or sides any Joints or Muscles, as hath the Ear-worm, as before is mentioned: besides the Wings of the Capellen are beautified with an infinite number of small Scaly Feathers, which are so curiously placed one Page  33 above the other, and do so wonderfully move the one from the other when the Wing is expanded, that it would deserve an intire Treatise: so wonderful is the wisdom of the great Creator seen in the shape of these Wings, and indeed what would not be wonderful of which he is the Author?

The (a)Ephemeron having thus quitted the water endeavoureth with all possible speed to attain a resting place on land, which having attained, it there (b) shed∣deth a second Skin, a very thin Film from its whole body, viz. from its Head, Breast, Belly, Legs, Tails, and Wings. And this second Skin shedding on land differeth from the first in the water; for in the first Skin-shedding the Worm loseth wholly its former shape, which it doth not in this second shedding.

In the first Skin-shedding, the Skin of the Worm bursting open on its Head & Back, suddenly falleth from its body and it as suddenly betaketh to flight, but with∣al loseth considerable parts, (c) all the Gills on both sides with the Ten Finns under them, besides these Gills thus shed there remain no hairs,* which disappear so intirely as to leave but very small Signs or points thereof, which on the side of the Belly make a kind of a small list. It looseth also * its Teeth or Sheres, the shape of its * Legs, the * Wing-Cases, the * Tails, &c. So that by this First Skin-shedding, it cometh forth wholly like (d) another Creature.

But although this order or method is very difficult, if not impossible to be observed, in this so sudden Change of the Worm; yet may it with much ease be discerned, if of a Worm thus ready for Change the Skin be slowly and with Art and Care taken of; for then the shedded Gills may be clearly seen remaining in the shed Skin; also there may be seen the remaining points thereof sticking out in the Flie; there may also be seen in the Skin the pits in which they stuck; in the same is also visible the shed Skins of the Air-vessels of the Muscles, the Arteries, Veins, Nerves which se∣parate Page  34 one from the other, like ripe fruit that falleth from the Tree.

Further, whereas the Flie in this First Skin shedding hath all its Joints and parts more extended in length, yet the horns barely shed their Skin without any further ex∣trusion, and become much tenderer and shorter in the Fly than they were in the Worm. But more consi∣derable is the Change about the Eyes, for the horny Film of the Eyes which in the Worm appeared even and smooth, after the Skin is shed in the Fly appeareth like a Net, being an aggregate of many Eyes. The Legs and two Tails after the Skin is shed, become double the length, and the third or middle Tail is also shed with the Skin.

When I say that the two Eyes in this Insect are made of an Aggregate of many small Eyes, which in some of these Insects, I have found to be 6 or 7000. and in some Insects spread up and down their body, as in Spiders, and the Scorpion Flie, it must not therefore be con∣ceived that they are in Form or make like the Eyes of other known Creatures, or men, for in these is found no Humour, but from every Globular partition of the same issueth a Sexangular Filament which terminates on the Net-like Film of these Eyes, and that in the Nerve and Brain, so that the manner of seeing in these Insects is wholly different from what it is in us, in whom it i effected by a Collection of Raies in the Eye, but in them by means of a Collection of Nervous Filaments, which when they see are only touched at the ends of their Convexities by the Visible qualities and Raies of Light and Colour, as I have mentioned at large in my Treatise of Bees.

Concerning the second Skin-shedding of the Ephe∣meron which soon succeedeth the first, it is observe∣able that the Ephemeron in seeking a resting place for to shed its second Skin is wholly incurious, resting on whatsoever is in its way, whether Wood, Stone, Earth, Beast or Man, and it is thus effected.

Page  35It fixeth its Feet armed with sharp Nails on what it first lighteth on, then being seized as with a cold shivering, the Skin splitteth open in the midst of the back in the horny integument of the same, which split increases forwards so far that the Flie can put forth its head, then it (a) draweth forth its Legs out of the Skin, while the Nails of the feet remain fast to that whereon the Flie had taken hold, which Nails remain with the shed Skin, and thereby furthers and facilitate the stripping thereof, First the Head and Legs are drawn out of the Skin, as you would pull your foot out of your Shooe, or Head out of a close sticking Cap, and then the Skin is drawn off the remaining parts of the body, by turning the inside of the same outwards, as we usually flea Eeles, or pull off a Glove the inside outwards, and when the Skin is half way over the Wings they are like (b) captivated and bound, and so remain a small time without any perceptible motion: the remaining part of the body in this second Skin-shedding is considerably extended, and the Tails be∣come a third part longer than in the first shedding, so that the Tails and Legs at the first shedding which became a Third part longer than before; are become in this second shedding ⅓ longer than they were in their first shedding, which yet is more considerable in the Tails, than in the Legs, for because it is composed of many hollow Rings which by extrusion shove one from the other, and thereby this stretching out is more visible in them than in the Legs which only lay bent in the Skin, and by the shedding thereof become extend∣ed in their full length. Further the hairs which in the Worm did thick beset the Tail, do stand now in the Tail of the Flie more thin set, and are become finer and thin∣ner, for that they have now also twice shed their Skins.

The Ephemeron having now a Second time shed its Skin flyeth again to the water, on whose Surface it flyeth sportingly, sometimes higher sometimes lower, Page  36 Sometimes swifter sometimes slower, and between whiles resting on its Tails beateth its Wings together, in the mean while its Tails supporting it which are hol∣low and beset with hairs, and being fill'd with Air, drive and Swim the better on the water without sinking, the which also happens to other Insects which by means of hairs in and between which the Air being inclosed they easily Swim on the Surface of the water as appeareth in the Worms of the Gnat and Gadflie, yet remain not these Tails always thus filled with Air, but become empty thereof if a pin be run through them to dry them, for by that means the Air issuing out, they fall in lank and crumpled: there is yet another reason that our Flie thus lightly driveth on the water, which is, that in its body it hath a fine bladder filled with Air, except it be said to be the Stomach, now only filled with Air, which I cannot strictly say, having not fully satisfied my self therein.

To proceed, this is here observable, that the (a) Male twice sheddeth its Skin, and the (b) Female but once which I cannot confidently affirm, yet have not hither∣to observed ought to the contrary, for this cause the Tails of the Female are ⅓ shorter than the Males. An∣other and more considerable difference is, that the Eyes in the Male are double in largeness to those of the Fe∣male; the third difference is, that the Gold colour of the body draweth-somewhat more to Red in the Male, than in the Female. Add hereto, that to the great Tails of the Male are four Appendices, which appear like crooked Tags, which in the Female are not so vi∣sible.

The Ephemeron Copulateth neither in the body of the Water, nor on Land, nor in the Air; only the Female shooteth her Eggs on the Surface of the Wa∣ter, on which the Male shooteth or casteth its Milt or Seed; to which end possibly it is provided with larger Eyes, that it might the better discern the Eggs of the Female in the water. As in like manner many sorts Page  37 of Fish, without any Copulation, cast their Seed in the water, which they eject not all at once in one body, but sparsedly as loose and separated Seeds. That the Ephemeron Copulateth not in the water ap∣peareth hence, for that they come not out of their Cells till such time as they are ready for Change, except they come out to take Air, and it were impossible for them to Copulate in the body of the water, for that they cannot keep themselves up in the water without constant motion; for at any time ceasing their motion they immediately sink to the ground, where they have no firm abode, till they have bored themselves new Cells. Add hereto as the strongest reason, that no In∣sect ever Generateth till having shed its last Skin, at least not by any observation of mine.

Neither do they Copulate in the Air, as may easily be perceived at the time when they flie; as also that it were impossible for them to Copulate in the Air, in consideration that after the last Skin-shedding the Legs of the Male are extended to that length that Clutius judged them to be horns. Consider also what requisites are necessary for to Copulate flying in the Air, as is observable in Flies, and chiefly in the Dra∣gon-flie, which perform the Act of Copulation very wonderfully flying in the Air.

I conclude therefore my Observation, that the Ephe∣meron never Copulateth either in the water or in the Air, but only that the Female having shed its Eggs in the water, the Male sheddeth thereon its Milt or Seed as before is said. All which in that short time of their life in this state is effected in that haste and swiftness that it is impossible to make a narrower search therein.

During the whole life of this Flie it eateth nothing, as is common to many other kinds of like Insects, and in some others, this not eating continueth for some weeks, yea months; as in Frogs, Lizards, Snakes and Camelions, as I have observed.

Page  38What I have thus observed concerning the Genera∣tion of the Ephemeron, is very considerable, but yet that is more considerable in the Snail, whereof each is both Male and Female together; which I doubt whether it is so in any other Animal. And although there are many Relations of those they name Herma∣phrodites, yet doubt I whether ever any such hath been seen. I opened once a Child reputed for such, but well examined, it was found a real Female; notwithstanding that above the Female parts it had a rising, out of which it evacuated its Urine, which hapned for that it had no Urine-bladder, and the passage of the Kidneys for evacuation was in that place, which caused the easie-believing and not considering people to believe this Child was of both Sexes. Among the Bees are Males and Females, and a sort that are neither; that we name among them the King, is a Female; the Breeder which is a Male, and the common Bee which is neither. The same is also among Ants. Again those Animals which grow fast to the Rocks, or live in hard Shells, and so remove not from their place, must needs have ano∣ther manner of Generating; all which compared with the Generation of Vegetables having both Sexes in the same body, and the power to Generate without Copulation, we may observe that the Omnipotent God can produce the same thing by several means and ways.