538 
FOREST AND STREAM 
November, 1917 
CULTIVATING SILKWORM GUT AT HOME 
THE ANGLER CAN GET GOOD TROUT LEADERS SIX TO NINE FEET LONG FROM THE 
CECROPIA, THE RUSTY RED MOTHS THAT HANG FROM THE BUSHES AROUND HOME 
By EDWIN T. WHIFFEN 
A fter a little experience, every angler 
with the fly, who is in the habit of 
studying the problems that con¬ 
stantly confront him, recognizes the im¬ 
portance of concealing the connection be¬ 
tween the line and the lure. Such a con¬ 
nection is established by means of the 
leader, consisting usually of Spanish gut. 
Now the desirable qualities in a leader are 
strength, fineness, and unobtrusiveness. 
The last essential depends upon color, ab¬ 
sence of luster, and of any small peculiar¬ 
ities which serve to call attention to any 
particular part of the leader. In its ordi¬ 
nary 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 ob¬ 
ject of the angler’s special interest—the 
artificial fl)'. The shine may be removed 
by the process of “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 colored, usual¬ 
ly a weakening process also. The knots, 
like the poor, we have with us always. 
As a result of the study o^ these con¬ 
ditions, 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 
Asiatic silkworm, the idea naturally pre¬ 
sented itself of endeavoring to substitute a 
caterpillar, larger and with larger silk sacs, 
for the insect from which the Spanish gut 
is derived. This substitute was sought for 
in the various American silkworms. Of 
all our American varieties, the caterpillar 
spinning the largest cocoon is the cecropia. 
An article on the Cecropia by Mr. 
Whiffen, published last winter in 
Forest and Stream, was so favor¬ 
ably received that we immediately re¬ 
quested him to treat the subject at 
length. This is the first of a new 
series of articles that he has pre¬ 
pared on the cultivation of American 
gut-producing caterpillars. It opens 
a wide field both interesting and 
profitable to our readers and will be 
continued next month. 
The general color of this moth is a rusty 
red. This is the color of the head and 
foreparts. It has a distinctive white col¬ 
lar. The abdomen is reddish, and has 
bands of black and white. The wings are 
grayish; bands of red and white extend 
across them. A characteristic is the trans¬ 
parent membrane, or eye-spot, which is 
found on the fore wing. A whitish cres¬ 
cent marks the rear wings, and the whole 
wing has a clayish-brown edge. The an¬ 
tennae, or “horns,” are broad and feathery, 
those of the male being much more so 
than those of the female, and furnishing 
an easy means of distinguishing the sexes. 
T HE full grown cecropia caterpillar, 
when very large, may measure nearly 
five inches in length, is moderately 
stout, and of an apple-green color. On the 
various segments of the body are tuber¬ 
cles, or shot-like appendages, mounted on 
the ends of little stalks. O'n the second, 
third, and fourth segments these tubercles 
are of a coral color. On other segments, 
the tubercles may be blue or black. The 
head is green with black markings. These 
characterize the full-grown worm. 
Next in size as a spinner of cocoons is 
the polyphemus. The moths are nearly as 
large as those of cecropia. They vary in 
color somewhat more than the latter moth. 
The general impression is a reddish or yel¬ 
low furry brown, with black scales pepper¬ 
ing the wings, on which are cross-bands 
of red, or pink, white, and gray. On each 
wing is the typical eye-spot, and a trans¬ 
parency surrounded first by a lightish 
brown circle, and a black ring outside of 
this. Like the cecropia, the sexes are dis¬ 
tinguished by the difference in breadth of 
the antennae. The color of the bodies is 
a dark or light tan, and the fore part 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, as the cecropia does. Hence 
the long thread may be reeled off, and 
might furnish a valuable fibre. The film, 
when 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, occasionally more. It is 
plumper for its length than the cecropia. 
The. general color is blue-green on the 
back and yellow-green on the sides. Yel¬ 
low tubercles are found on the back and 
sides, arranged in lines. 
A caterpillar much resembling polyphe¬ 
mus is luna. The line on the anal plate is 
yellow, instead of brown. 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 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. 
Polyphemus Moth—One-quarter Life 
Size 
An imported variety, from China, is the 
cynthia, or ailantus, silkworm. Its cocoon 
and method of attachment resemble those 
of promethea. It produces a slightly 
longer and larger length of gut. 
A S a fact, none of the American silk¬ 
worms are worth bothering with as 
gut-producers in comparison with ce¬ 
cropia. 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, luster- 
Cecropia Caterpillar 
less, and knotless. Polyphemus is not 
worth raising, if cecropia can be obtained. 
By hunting, available material for the 
