CULTIVATING SILKWORM-GUT AT HOME
BY EDWIN T. WHIFFEN
After a little experience every angler with the fly who is in
the habit of studying the problems that constantly confront him
recognizes the importance of concealing the connection between the
line and the lure. Such a connection is established by means of the
leader, consisting usually of silkworm-gut imported from Spain. Now
the desirable qualities in a leader are strength, fineness, and
unobtrusiveness. This last essential depends upon color, absence of
luster, and of any small peculiarities which serve to call attention
to any particular part of the leader. In its ordinary state, the
Spanish gut offends against all three just-mentioned qualities; its
color is obtrusive, it possesses a shine that makes it a target
for every eye, and the frequent knots mean just so many points to
distract the fish’s attention from the object of the angler’s special
interest--the artificial fly. The shine may be removed by one of the
processes known as “drawing,” that is, taking off the outer layer of
the gut by means of sandpaper; but this unduly weakens the product.
The leader may be artificially colored, and this also is usually a
weakening process. The knots, like the poor, we have with us always.
As a result of the study of these conditions, I became convinced
years ago that a substitute for the Spanish-gut leader was a matter
of desire for the angler.
As the Spanish “gut” is the product of the silk-sacs of the Asiatic
silkworm, the idea naturally presented itself of endeavoring to
substitute a larger caterpillar, and one with larger silk-sacs, for
the insect from which the Spanish gut is derived. This substitute
was sought for in the various American bombycid (family _bombycidæ_)
or silkworm larvæ. Of all our American varieties, the caterpillar
spinning the largest cocoon is that of the cecropia moth (_Platysamia
cecropia_). The general color of this moth is a rusty red or brown;
this is the color of the head and foreparts. It has a distinctive
white collar; the abdomen is reddish, and has bands of black and
white; the wings are grayish with bands of red and white extending
across them. A characteristic is the transparent membrane or eye-spot
which is found on the fore wing; a whitish crescent or kidney-shaped
spot marks the rear wings; and the whole wing has a clayish-brown
edge. The antennæ or “horns” are broad and feathery, those of the
male being much more so than those of the female and thus furnishing
an easy means of distinguishing the sexes.
[Illustration: Cecropia caterpillar]
The full-grown cecropia caterpillar averages from three to four
inches in length but when very large may measure nearly five inches,
is moderately stout, and of an apple-green color. On the various
segments of the body are tubercles or shot-like appendages mounted on
the ends of little stalks. On the second, third, and fourth segments
these tubercles are of a coral color; on other segments they may be
blue or black. The head is green with black markings. These features
characterize the full-grown worm.
[Illustration: Polyphemus caterpillar]
Next in size as a spinner of cocoons is the _Telepolyphemus_. The
polyphemus moths are nearly as large as those of cecropia, and they
vary in color somewhat more than the latter moth. The general
impression is a reddish or yellow, furry brown, with black scales
peppering the wings, on which are cross-bands of red or pink, white,
and gray. On each wing is the typical eye-spot, and a transparency
surrounded first by a lightish brown circle, and by a black ring
outside of this. Like the cecropia, the sexes are distinguished by
the difference in breadth of the antennæ. The color of the bodies is
a dark or light tan, and the forepart has a gray band. The cocoon
is ovoid in shape, when first spun looking as if dusted over with
lime; later the color is brown. The caterpillar spins on practically
the same kinds of bushes or trees as the cecropia. In the spinning
process, the worm does not break the thread to form a means of
egress at the front of the cocoon, as the cecropia does; hence the
long thread may be reeled off, and might furnish a valuable fiber.
The film when thus unwound from the cocoon has a beautiful silver
tint, and is surprisingly strong for its size.
The caterpillar reaches an extreme length of three inches or little
more, and it is plumper for its length than the cecropia. The general
color is blue-green on the back and yellow-green on the sides. Yellow
tubercles are found on the back and sides, arranged in lines.
A caterpillar much resembling polyphemus is luna (_Actias luna_). The
line on the anal plate is yellow, instead of brown, and the worm is
of a different shade of green; and thus may be readily distinguished.
It spins a thinner cocoon, and probably has little value as a
gut-producer.
Among the smallest of this class of the moths is the _Callosamia
promethea_, whose method of attaching its cocoon distinguishes this
phase of its existence from the preceding varieties. A handle, like
an umbrella’s, securely holds the cocoon to the twig or leaf-stem.
This is a pretty little moth, but the results of my experiments with
it go to show that as a producer of gut it is a failure, the strand
being small, short, and weak.
An imported variety, from China, is the cynthia or ailanthus
silkworm. Its cocoon and method of attachment resembles those of
promethea. It produces a slightly longer and larger length of gut.
As a fact, none of the American silkworms are worth bothering with
as gut-producers in comparison with cecropia; although I have
secured fairly good, stout strands of gut, four or five feet long,
from polyphemus. But my experience has been that a small cecropia
caterpillar produces as much gut, and of a better quality, than a
large polyphemus; while a big cecropia is unapproachable in this
respect, yielding a strand of gut from six to nine feet long, round,
smooth, of a suitable color, lusterless, and _knotless_. Polyphemus
is not worth raising if cecropia can be obtained.
[Illustration:
Polyphemus moth--one-quarter life size ]
[Illustration:
Promethea--half-grown worm, adult, and new cocoon, on one bush ]
By hunting, available material for the cultivation of these worms may
be obtained in the shape of moths, cocoons, eggs, and caterpillars,
the cocoon state being on the whole the most satisfactory. In length,
the cecropia cocoons vary from somewhat over an inch (very small)
to three inches (very large). Some are slender and compactly spun,
others are loosely spun and baggy. They vary in color, when fresh,
being brownish, and when weathered, somewhat silvery. They are more
pointed at one end than at the other. Careful examination of this
pointed end shows that the threads were broken and then puckered
together in the process of spinning. The cocoon usually is attached
to the side of the twig, branch, tree-trunk, or stalk on which the
caterpillar has chosen to spin. The caterpillar may elect to spin on
its food-plant, or it may wander away and spin on almost any suitable
stalk or twig. Its cocoon has been found on maple, willow, woodbine,
oak, plum, elder, wild cherry, spicewood, apple, pear, nettle, wild
hemlock, sumach, ailanthus, and other varieties “too numerous to
mention.”
It is worth while to look almost anywhere in a locality in which
cocoons are being found. Usually there is more or less of a little
colony discoverable where a single cocoon has been discovered. You
may pick a cocoon plastered to the trunk of a tree at its very root,
or attached to a shoot but a few inches from the ground; then as
you glance up you notice the brown, baggy bunch thirty feet in the
air, spun alongside the tip of the twig. No place is too unusual or
insignificant to be overlooked, though one soon develops a special
sense in searching.
Your equipment for cocoon-hunting need not be elaborate. There are
some things that are helpful, if not really necessary. You can put
in your pocket the cocoons that you find, if you wish, though there
is danger of crushing them; a bag or a box of some kind is better.
If you are abroad in the Spring, when the moth is laying its eggs,
some little paper or tin boxes will make good receptacles for your
“finds.” In the same season you will need larger boxes in which to
put any moths you may capture, and a net will be necessary for taking
the specimens. In Summer or early Fall, the caterpillar season,
some boxes large enough to hold your captures without crushing them
will be advisable. As for clothing, wear the oldest and toughest you
have. It is not especially conducive to the beauty of head-, foot-,
or body-gear to go crushing through bushes, briars, and shrubs, over
bogs and swamps, or to crowd up trees and into other places difficult
of access in which some caterpillars seem to have taken a fiendish
delight to spin. An umbrella with a crook for a handle is helpful in
pulling down branches or twigs just out of one’s unaided reach, where
frequently fat cocoons are attached. A fish-line with a weight on the
end is serviceable for bringing down those branches a little too high
for the umbrella. If you are working among trees of any size, a long
pole with a triangle-hook attached will enable you to reach cocoons
spun by worms of the most aspiring spirit. The most valuable item
in your equipment you will not be able to take with you at first--a
general ability to distinguish good territory from bad and to “smell
out” every specimen in the locality.
Let us suppose it is Fall or early Winter, and you are hunting
cecropia and polyphemus. You should follow along the road or street
studying carefully the trees and shrubbery. Luckily enough for the
hunter, cocoons as a rule are not found in high, dense vegetation or
inside of groves or woods. Circle around the outside of such places,
studying carefully every tree and shrub, low or high. Examine any
tuft of leaves or protuberance on twig or trunk. Pass over nothing
that at all suggests what you are in search of. Sometimes it is a
good plan to study a clump of bushes or a tree from one direction and
then slowly circle it so that the light will be thrown on the leaves
and limbs from various angles.
If you are in the street, you may collect a small crowd anxious to
see “what the gink is rubberin’ at,” but a true explorer never pays
any attention to little things like that. A vacant city lot which
has many or few bushes, stumps with sprouts springing from them,
little, weazened trees that almost apologize for living, sometimes
yield surprising finds. A lane in the suburbs with trees and bushes
on either side furnishes good hunting-ground. If there is a wall on
either side with a vine of some sort growing upon it, you may find
that careful search will reveal brown, baggy bunches that prove to
be cecropia cocoons. Patches of scrub white-birch or spice-bush
should always be carefully examined, as such places often harbor many
cocoons.
Cocoons may be hunted for at any time after the spinning season until
the warm Springtime weather causes the moths to emerge from the
cocoons. As soon as possible after the falling of the leaf is the
best time, as certain birds tear apart the cocoons and eat the tender
pupæ within. Places in the cities and suburban towns are usually more
productive of results to the cocoon-hunter, not necessarily because
there are more cocoons, but because the cocoons are more in view and
closer together on account of there being fewer trees and shrubs to
attract the female moth as it lays its eggs. Almost the best place
of all is a field with numerous scattered clumps of willow, maple,
spice-bush, or alder; these usually are small and accessible. The
adult moth, on its egg-laying mission, seems to find dense vegetation
a hindrance and hence avoids it.
The caterpillars probably do not stay many feet from the spot where
they hatched from the egg; indeed, the worm may pass all stages of
its life-history and spin its cocoon on a single shrub. Sometimes
such unpromising spots as backyards are well worthy of search. The
egg-laying function of the moth is compulsive and the eggs must be
laid wherever the parent may chance to be at the proper time of
depositing them. It has from two hundred to six or eight hundred eggs
to dispose of in a comparatively short time, and cannot afford to be
too nice as to the character of the place where it deposits them.
[Illustration:
Cecropia cocoons of different size and shape ]
[Illustration:
Cecropia cocoon showing the details ]
The American silkworm caterpillars have various parasitical enemies,
particularly varieties of the ichneumon-flies. The adult parasite
lays its eggs on the body of the caterpillar; there hatch out and
the tiny worms proceed to eat their way into the body of their host,
which soon may die. Or the caterpillar may live long enough to
perform its functions of spinning but then dries up and dies. Or
the parasite may construct a peculiar kind of cocoon within the
larger one spun by the host; such specimens are interesting to the
scientist but valueless to the one who wishes to rear caterpillars
from the egg. As a rule, specimens which have not pupated are
easily distinguishable from good ones. The silk of such cocoons is
thinner, and when the cocoon is shaken close to the ear a peculiar
dry rattle is heard; a good specimen when similarly treated gives
a characteristic, unmistakably solid _thud_. Those specimens in
which parasites have pupated are not thus distinguishable; only by
opening the cocoon and examining the contents can the counterfeit
be detected. It is not well to disturb the pupa in this way; it
is better to watch carefully for the emergence of the wasp-like
ichneumonides, which should be destroyed when they are perceived.
While the idea of collecting the cocoons and of getting a supply
of eggs from the moths is unmistakably the best plan, do not be in
despair if your cocoon-hunt is unsuccessful. You may be able to
capture one or more fertile females in the Spring, which will supply
you eggs from which enough caterpillars will hatch to keep you
sufficiently busy. For this variety of “bug-hunting” you will need a
net of some light mosquito-mesh, with tin or paper boxes in which to
stow away your captures.
The American silkworm moths generally fly by night, and the electric
light is hence a blessed institution to the moth-hunter. These
creatures, some of them as large as a small bat, or, perhaps a better
comparison, as broad as your hand, and of the most entrancing beauty
in shape, color, and silken flight, will throw even the beginner into
raptures at their sight. Some alight gracefully and stand slowly
furling and unfurling their wings, as if pardonably proud of their
beauty. Some float like a many-hued shadow to and fro. In either case
a skillful turn of the net effects a capture. A morning search is
sometimes profitable. The moths are occasionally found hanging to the
roofs or beams of sheds; the undersides of bridges, if near lights,
are likely places. Sometimes you will see the moths bobbing against
the window-screen from the outside, where they may be taken. The
cecropia, especially the female, throws off a peculiar “animal odor,”
by which it may be tracked to its hiding-place in the daytime. This
odor is exceedingly strong, almost offensively so, and is carried by
the wind to a considerable distance; it aids the male to find the
female, at the mating season. Once smelled you will never forget it.
At this time of the year, egg-hunting may yield fair results.
Suitable places evidently are about the same as for the cocoons.
You should carry along tin boxes with covers, in which to place the
leaves upon which the eggs are found; remove the leaf entire, to
avoid injuring the eggs in any way; examine both sides of all the
leaves of shrubs in a promising locality.
Cecropia eggs are of an ovoid shape. On the upper side is a reddish
spot, and they are about as large as quite small bird shot. The
polyphemus lays white, brown-banded eggs which are larger than
those of cecropia. Both species deposit eggs in a variety of ways,
sometimes singly, sometimes in a short row, or in peculiar little
masses.
Last, and least satisfactory of all, is the method of attempting
to find the caterpillars. They hide away so cunningly as to be
nearly undiscoverable, even when the signs of their presence are
unmistakable. Such signs are wholly- or partly-eaten leaves and the
presence of excrement on the ground beneath. Just previous to the
actual spinning, the worm may crawl along in an excited fashion, as
though anxious to reach a certain spot on schedule time; it may then
be found almost anywhere, running up or down a tree trunk, or along
the road, or across a walk. Such specimens do not ordinarily give a
satisfactory strand of gut, as the chances are against their having
eaten of the kind of leaf that results in the best variety of that
product.
In case you have secured a reasonable number of cocoons, twenty or
so, it is best to put them away in a cold place during the Winter.
A good plan is to place them in a small screen-cage and expose them
to the weather outside; the moisture and the cold of Winter will not
work any injury but will keep the cocoons and their contents from
becoming too dry. If they are not thus exposed, it is well to turn
them occasionally and sprinkle them lightly with water.
When the weather becomes warm in Springtime and the leaf-buds begin
to appear, bring your cocoons into a warm room, when the moths soon
will begin to emerge. If so situated as to be able to have a room for
rearing purposes, the moths may be allowed to fly around free from
confinement. If a male and a female of the same species emerge at
about the same time, they usually will mate without any difficulty.
After the completion of this function the male soon dies, and the
female immediately begins to deposit eggs. It lays several hundred
in the course of a few nights, and then dies too, neither sex living
more than a week or ten days. In case a female or females alone
should emerge from the cocoon stage, a mate must be secured if the
eggs are to be fertile. This is done by exposing the female out of
doors, either in a screen-box with large interstices or else by
securing her by tying a length of woolen yarn about her “waist,” the
other end of this tether being made fast to prevent her escape. The
former method is preferable, as bats and birds are fond of a tender
moth. If you place the captive moth outside the window, be sure that
it is on the side of the house opposite to the direction in which
the wind is blowing, so that the scent may be carried farthest and
be most likely to attract a mate. If your attempt is successful, the
evidence usually will be found in the presence of the male in the
morning.
The fertile female moth should be placed in a pasteboard box with
a cover, such as a shoe box, where it will “get busy” and plaster
every available place with eggs, at the same time battering its
beautiful wings pitifully. As soon as all the eggs of a moth have
been deposited, on the sides, bottom, and cover of the box, with a
sharp knife remove them on a little bit of the paper, being very
careful not to crack the hard, shiny shells, as they will thus be
spoiled. Put the eggs, thus removed, into _tight_ tin-boxes or glass
jars (Mason jars), and put the covers on tightly unless you wish
to find wandering baby caterpillars, looking for “something good,”
scattering over the neighborhood. At all times, but especially when
they are small, should tight receptacles for your worms be supplied,
as they will go through a pin-hole, with several feet to spare in
every direction, for they are great roamers.
The hatching period may be as short as seven days, but usually is ten
days, or even more if the weather is cool. Shortly before hatching,
the eggs become quite dark in color; then the little “darkies” eat
a hole and crawl out, soon looking too large ever to have been able
to get into so small a compass. Their appearance should have been
carefully watched for, and food leaves have been supplied as soon
as the little, black worms were seen. The freshly-hatched cecropia
caterpillar is about a quarter of an inch long, black, and with
little black bristle-like tubercles. Occasionally I have had freaks
in a brood, such specimens being a deep yellow in color. Any kind of
leaf which the young caterpillar will take is suitable food for the
first three stages of its existence; one year, when I had a brood
hatch early in April, I fed them on the leaf of some perennial shrub
which supplied the only “garden sass” then available. I have seen it
stated that the young Asiatic silkworm may be fed on lettuce for a
few days, till better food may be obtained, but my experience with
the young American silkworm is just the contrary; broods coming out
before the leaves opened have “turned up their noses” at tender
lettuce and stolidly succumbed to starvation.
Apple, pear, currant, peach, plum, berry of all kinds, bay, hard
and soft maple, mountain laurel, apricot, may be fed to them, some
broods preferring one kind, some another. They eat voraciously, with
a peculiar movement; supporting themselves by the false legs or props
on the latter half of the body, and grasping the edge of the leaf
with the sharp-pointed true legs, they raise the head and set the
mandibles into the edge of the leaf, then bring the head slowly down,
at the same time cutting the leaf away with their rapidly-moving
jaws--somewhat as the barber’s instrument “dehaired” our locks just
before the summer vacation, “to keep the boys cool.” After a full
meal the caterpillar rests awhile, digests its dinner, and then goes
at it again. No wonder they grow like pigs!
In a few days the caterpillar’s size has so increased that its skin
is too small and must be exchanged for a larger one; in fact, the
larger one already is developing. The caterpillar then “moults”; it
refuses all food and ceases to move about, remaining still as if
dead. If lightly touched, it jerks from side to side to testify its
displeasure at being disturbed. It should be treated with great care
as it is very easily injured at this time. Do not touch it with the
hands at all if you can possibly help it; lift it, if necessary, by
the leaf or twig to which it clings. Indeed, at all times handle your
worm like Izaak Walton’s frog, “as though you loved him;” the tender
skin is easily torn, then infection may set in and death follow.
After a period of two or three days thus spent, the caterpillar is
ready to moult. The mask-like headpiece may be seen hanging down in
front of the face; and the colors of the caterpillar are dingy and
dirty. Then the worm begins to wriggle; the old skin splits near the
head, and the caterpillar, bright and fresh as though newly enameled,
crawls out--like an emblem of the resurrection. Sometimes the “mask”
attached to the head is not shed with the rest of the skin and must
be carefully removed. After the first moult the caterpillar regains
its original color.
At all times be careful to have the receptacles for your worms
scrupulously clean; every day remove the wilted leaves and dead
caterpillars and thoroughly clean their quarters with a stiff brush,
taking out every particle of dirt. Do not pull the caterpillars from
the old leaf; put the fresh leaves into the cage and the worms will
leave the old for the new, and the old ones may then be removed.
A few fine drops of water should be sprinkled on the leaves every
day, which the caterpillars search out and slowly drink them; but
do not put in enough water to saturate the air in the receptacle.
As for the receptacles or cages themselves, small tin-boxes will do
well enough at first, but glass jars are better as their rounding
bottoms are more easily kept clean. Give your specimens plenty of
room, putting only a few into one cage unless it is very large. While
the caterpillar has no objection to eating in the dark and under any
circumstances can “get its hand to its mouth,” I prefer a transparent
cage, as then I can more readily keep track of the progress of the
inmates. These cages may be nearly air-tight as worms respire very
little.
Dry, roomy quarters are essential to prevent the development and
spread of certain fungoid diseases. If conditions are not right
the caterpillar loses its appetite; its plump, firm appearance is
changed to a thin and watery one; its skin cracks, and a whitish mold
appears which soon kills the diseased worm. Dead or sickly specimens
should be removed at once; and the cage should be thoroughly scalded
and dried to kill any remaining germs. A little precaution, taken
every day, will prevent such disastrous happenings and assure the
successful maturing of the brood.
While I have been writing, the caterpillars have been feeding and
growing; in a week or so they have developed sufficiently to be
ready for the second moult. The process of resting, cessation from
feeding, and shedding of skin is repeated; after this moult the color
is distinctively yellow, and the larger tubercles are apparent. The
worms should now be thinned out, some in each cage being transferred
to another. Always be sure that the new receptacle is clean.
Remember, the conditions of success are two: perfect cleanliness,
and sufficient food of a proper kind; under these conditions the
caterpillars thrive like young chicks. After a somewhat longer period
of feeding--and they will keep you busy gathering leaves--they moult
for the third time. At this stage their heads are green with black
markings; the bodies have become yellow and have two rows of black
dots running from “stem to stern”. The large black, red, and yellow
tubercles might cause them to be thought in the final stage; but
they now crave more food than before and fairly cram themselves with
the leaves supplied to them. At this stage you should begin feeding
the _leaf suited to insure the very best quality of gut_. I have
found this to be, first, fleshy, juicy leaves from the plum tree, and
a close second, the prickly leaves of the long blackberry, which the
caterpillars munch down with much gusto. You ought to have left, in
spite of accident, disease, and death, at least half or two-thirds
of your hatching, or some two hundred or so healthy and flourishing
crawlers. Listen as they eat, after you have put in fresh leaves for
them in the morning; the sound will remind you of a gentle fall of
rain in Summer.
If they ate before, they cram, gorge, distend, stuff themselves now.
In a week or ten days they should be ready for the final moult, from
which they emerge hungrier than ever. Their color is much as before,
but the size of the head seems enormous. In a week or ten days more
they have grown to be four or five inches long and are very plump
and sleek; then they cease feeding and prepare for the important
process of spinning. First they empty the digestive system entirely,
excreting a thick, syrupy fluid. Up to this time the excrement had
been fairly firm, and this marked change in its consistency is an
indication that spinning may be expected soon.
During the last stage it is a good plan to put the worms out of
doors to feed, selecting the most suitable food-plant for them, as I
have thought that the gut produced by this treatment was of superior
quality. Whether that idea is fancy or fact may be debatable; but
this I do know, that it is much easier for the one who has the job of
looking after it to bring the worm to its fodder than to bring its
fodder to the worm. They may grow somewhat larger in this way, as
there is never any lack of food; and especially at this stage they
eat so fast that they need feeding two or three times a day, instead
of only once as during the previous moults. Now, and especially when
I had large numbers, I have sometimes used small branches with their
leaves placed in Mason jars containing water; although I found a
tendency on the part of the caterpillars to crawl down after a drink
and so drown themselves. My usual method of feeding has been to put
the loose leaves (cut or torn on the edges when the caterpillar is
small) right into the cage, and to change food at least once a day.
Some labor can be saved by using this plan of putting the twigs
with leaves into bottles or jars containing water; but to prevent
the untimely loss of some of your “star boarders,” wind wool or tie
cotton around the twig just above where it enters the neck of the
bottle or jar, so that all suicidal actions may be frustrated. Once
I matured a brood of cecropias by means of the “branch-and-bottle”
method, on the top of a square piano; the jars tipped over sometimes
and the water ran down into the “inwards” of the instrument, but it
was only the piano that suffered--the worms thrived.
[Illustration: Section of Asiatic silkworm (enlarged) showing
silk-sac and spinnerets]
When, then, you find the soft, fluid excrement in the cage you may
know that one or more of the caterpillars soon will begin to spin.
The worm shortens somewhat, as the body-cavity contains little except
the empty digestive system and the sacs with the fluid silk. These
are two, long, transparent tube-like organs, each about eighteen
inches long, of about the diameter of a steel knitting-needle, and
curiously coiled and involved in the cavity of the body. At their
front ends they connect with small tubes or spinnerets through which
the caterpillar forces the fluid silk in shaping the material with
which it spins. The spinning process is a most interesting one. When
it is imminent the caterpillar crawls restlessly around, seeking a
suitable place, and a short film of silk may be seen hanging down
from its mouth. If you want to keep some cocoons over Winter for the
next season, put the prospective spinner by himself into a glass
receptacle with a few leaves, and watch proceedings.
After satisfying itself that it has selected a suitable place, the
caterpillar firmly grasps a twig with the false legs or props, and
with the true legs on the forward part of the body pulls the ends
or sides of leaves together. Then the head moves up and down, back
and forth, a film of sticky silk meanwhile gripping the leaves and
holding them together. The worm works industriously, and soon the
general outline and size of the cocoon appear, half-hidden in the
leaves. In a few hours the caterpillar has spun sufficiently to
hide itself from sight. If you wait a week or so and then carefully
open the end of the cocoon, you will see an interesting sight; in
place of the caterpillar, which was the last living thing observed
in the cocoon at the beginning of the spinning process, a brownish
pupa is seen, being a sort of case containing the embryonic organs
of the future moth. Most of the cocoon, inside of the closely-woven
exterior, will be a mass of fluffy silk-filaments surrounding a hard
inner case, apparently lined with some compact, gum-like substance
and containing besides the pupa the cast-off skin, now shriveled,
brown, and crowded out of the way into the back of the cocoon.
Of course you will want to draw the gut from most of the worms which
you have raised. The first important matter is to know the right time
for the operation. After a little experience you will be able to
tell by the film hanging from the caterpillar’s mouth that the worm
is what is technically known as “ripe;” but until that proficiency is
developed you will more safely wait until the spinning has actually
begun. Then prepare the solution in which to pickle the ripe worms.
The proportions are: a sufficient quantity of vinegar (depending
upon the number of worms ready) into which put enough salt to make a
saturate solution, diluted with the same quantity of water. The salt
should be put in the vinegar and thoroughly stirred until all the
salt possible has been dissolved. Pour off the vinegar, leaving the
undissolved salt, and then add the equal quantity of water. I have
thought that vinegar in which the “mother” had formed was best for
the purpose. You need not prepare more than a cupful ordinarily, as
the caterpillars will ripen only a few at a time; and many of them
may be pickled in one solution before it is used up. The purpose of
the pickling process is to toughen the silk-sacs sufficiently to
permit of their being pulled out. Into the solution, prepared as
above, put whatever worms may be ready to spin, first tearing them
across the back at about a quarter or a third of the distance from
the head; but do not entirely remove or separate the torn portion of
the worm.
While the pickling process is proceeding let me say that some have
drawn gut without putting the worm into a solution of any kind.
I have tried this method on cecropia and polyphemus, but with
unsatisfactory results. I am not denying the possibility of doing
it; I merely am stating my own experience. I try a few worms by
this method from every brood that I raise, and hope some day to
be successful. My experience has been that the unpickled sacs are
too weak to permit of being drawn out in this way; however, I will
describe this method in hopes that it may be useful to others. Take a
board from six to nine feet long. Pin the worm securely to one end,
putting one pin through the “tail” of the animal and two more about a
third of the way back from the head. With a sharp knife cut off the
anterior part back nearly to the two pins. Take a large pin and dip
it into the silk and carefully draw out as far as the fluid silk will
go, and fasten each strand with a pin; a cecropia caterpillar has two
silk-sacs and yields two strands of gut. Let the gut thus drawn out
dry in the shade for several days. I have read that a method like
this has been successfully tried in France; but I must confess that I
do not enjoy the experience--neither does the worm. Very likely the
caterpillar could be killed or stupefied by some means before the
pinning was done.
The method which I employ has at least the merit of being more
merciful. After the worm has pickled for about half an hour I examine
and draw out one end of a sac; and if it is strong and firm I
continue the drawing process. If there is a suggestion of weakness
I continue the pickling process fifteen or twenty minutes longer. I
am convinced by experience that the precise moment for pulling out
the sacs is a highly important consideration. If the pickling has
been too short, the gut, while apparently strong and of good quality,
seems to be lacking in the proper consistency; on the other hand, if
the pickling is carried too far, the resulting strand is lumpy, and
the lumpy parts while looking strong are really the weakest.
I do not feel that I can describe the exact point for drawing at
which results are likely to be the best, though I could easily show
to another the silk-sac when it had the proper consistency to assure
them. But I will attempt a description, as even a poor one may be of
some help though experience and observation are the best instructors.
At its best condition for securing results, the sac on being removed
from the body of the worm has a peculiar whitish appearance, not soft
or mushy and yet not hard like a string of glue. The strand when
pulled out suggests in appearance a tendon or “cord,” such as is
found in meat before cooking it--it has a peculiar, “glairy” look.
This color becomes somewhat opalescent on drying and later may turn
even dark brown.
Having satisfied yourself that the sac is properly pickled, work
quickly, since there are, as stated, two strands to every worm and
the pickling process must not unduly be prolonged. On the shady side
of the veranda or of the house stick a pin into the clap-boards and
tie to it securely one end of the sac. Then take the other end of
the sac in the fingers or tie it to another pin and draw the gut out
to its full length. If any parts of the sac are not fully drawn out
these will be lumpy and weak when the gut is dry. Fasten the end of
the sac just drawn out and allow it to dry for several days. While
the gut must be stretched far enough to keep it from being lumpy, a
little allowance must be made for contraction in the drying process;
so ease up an inch or two before both ends of the gut are made fast.
I have had very good success when the gut was drawn on a rainy day
and the strands became moist and slack; in such circumstances I have
thought that the gut was peculiarly strong. But at all events keep it
out of the sun, and if it contracts so much as to pull out the pin
at either end, refasten with the tension eased up somewhat. In a day
or two you usually will find that you have a variety of colors; some
will turn a dark golden-brown, some may have a bluish tint, others
will be light like a washed-out rootlet or fiber, and still others
will approximate in shade the ordinary Spanish gut but will lack the
“shine” which the latter unfortunately possesses.
Restrain the tendency to use the freshly-drawn gut too soon;
although it may be fine in texture and apparently strong, it should
thoroughly mature for several days or even weeks, for best service.
Once properly prepared, it will give good use for years. I have in
my possession two leaders drawn ten years ago, yet they still are
reliable.
I had to learn by experience that a careful maturing of the product
is essential to success. On one occasion I had drawn several hundred
leaders, but they were placed in a tin box before they were dry and
were stored in a damp place; on examining them several weeks later I
found about twenty of them still good, but the rest had become ruined
from mildew.
Do not expect that every leader you draw out will be a good one. The
Spanish gut sold in this country is but a small part of the total
product, and not one strand in a hundred is perfect. So, much of
your product will come out flat and weak, like the inferior strands
of Spanish gut, due perhaps to improper pickling, the wrong kind of
feed for the caterpillar, or to an unhealthy worm. A considerable
number will be of fair strength, testing to three or four pounds, and
sufficiently strong for brook-trout fishing; and occasionally you
will get a fine specimen, long, round, and strong enough to hold a
bass on fly tackle.
[Illustration:
Cecropia moth, which in life may have a five-inch wing spread
Two of Mr. Whiffen’s one-strand, home-grown Cecropia leaders, six
feet long ]
Naturally the strands will require testing to select the good from
the bad. Tie a loop in one end of the strand and attach it to a hook
or nail in the wall. Give it a moderately strong pull, holding by
the other end. If the strand breaks easily or near the middle, it
usually is wise to discard it, although it may be fine in texture and
apparently strong; yet I have had strands break near the middle in
this way, which on being fastened together by loops made successful
leaders. The thin end usually is the weakest part and may break off
a few inches at a time till two feet or more have been removed. Now
take those that stand this preliminary test successfully and give
them a more severe one. Take a milk bottle, for example, and put
enough water in it to make it weigh say three pounds; then attach
the strands to be tested and see if they will raise, one at a time,
that weight. If they do they are strong enough for trout-fishing with
light tackle. If you desire to select any leaders for bass fishing,
some which will show a greater strength, study very carefully the
leaders you have just tested and take the largest, strongest-looking
strands and with your milk bottle filled to five- or six-pounds’
weight, test them again. A fair proportion of the gut drawn from a
brood of cecropia worms should stand this latter test.
With regard to those leaders that have “come through,” you will have
a product from six to nine feet long, of a slight taper, uniform in
consistency, even in color and strength, and which in appearance will
surpass the Spanish fine drawn-gut.
In one respect the inferiority of the American product must be
admitted; I have not yet succeeded in producing a strand of gut that
will test to ten or twelve pounds, as I understand an occasional
strand of Spanish gut has done. Still, the extreme length of the
imported article is eighteen to twenty inches, while the native
product is three or four times as long. Strands tied together are not
as strong as the single one, because the knot is the weakest part of
the leader; therefore a leader testing up to eight or nine pounds
is a very strong one. It is not improbable that a better variety of
food, or a different pickling solution, or a careful breeding of
worms to secure desired qualities, may produce an article superior
to anything which I have been able to get, thus far. I have gone
about the matter in an amateurish way and have produced results far
exceeding my first hopes.
I consider the field a promising one. A first-class salmon-leader,
for instance, is listed at five dollars, and is the product of
several Asiatic silkworms. A cecropia strand of equal length and
testing up to four or five pounds has been produced. As already
noted, a cecropia caterpillar has two silk-sacs and yields two
strands of gut. It is possible, therefore, that with really
scientific study and manipulation one cecropia worm might produce
ten-dollars’ worth of gut. If one caterpillar in a hundred did,
the occupation of raising them would be profitable. The raw
materials--cocoons, moths, eggs, or caterpillars--cost nothing to
collect, and at present very little to buy. Surely some person of
more scientific bent than myself, with persistence and research, will
work out a product which will be the best of its kind.
LANDING-NETS AND OTHER EQUIPMENT