Prof. C.V. Riley, entomologist, announces that the Department of
Agriculture, Washington, will purchase during the coming summer such
quantities of silk worm eggs as may be deemed necessary for the
distribution that it is proposed to make for the season of 1886. So far
as found practicable, the eggs will be purchased of American producers.
There are certain precautions, however, that must be taken to insure
purchase. Eggs of improved races only (preferably of the French or
Italian Yellow Races) will be bought, and the producer should send one or
two samples of pierced cocoons with the eggs. In addition to this the
producer must conform to certain rules to be hereafter explained, so that
an examination may be made that will serve to show the degree of purity
of the eggs. No silk culturist should use his crop for the production of
eggs unless the worms have shown, until they began the spinning of their
cocoons, every sign of perfect, robust health. Any indication of the
disease called _flacherie_, from which the worms so often die after the
fourth moult and turn black from putrefaction, or of any other disease
from which silk worms suffer, should be considered as ample reason for
not using the cocoons for the purpose in question. They should, on the
other hand, be sold for the filature. If the worms have all the
indications of health until the spinning period, then the cocoons may be
used for the production of eggs. The following brief instructions will
prove of service to those who which to secure sound eggs:
[Illustration]
For each ounce of eggs to be produced, about three-quarters of a pound of
fresh cocoons from the finest and firmest in the lot should be chosen.
These should be strung in sets upon a thread, care being taken not to
pierce the chrysalis, and the strings hung in a cool, darkened room. The
moths generally emerge from the cocoons early in the morning, and will be
seen crawling about over these, the males being noticeable by their
smaller abdomens, more robust antennae, and by their greater activity. The
moths should be placed, regardless of sex, on a table, where they will
soon find their mates and couple. As soon as formed, the couples should
be removed to another table, that they may not be disturbed by the
flutterings of the single moths.
There should be prepared for each ounce of eggs to be produced, about
one hundred small bags of fine muslin, made in the following manner: Cut
the cloth in pieces 3×6 inches. Then fold one end over so as to leave a
single edge of about three-quarters of an inch, as shown in the
accompanying cut. This should be sewn up into a bag with the upper end
open, and then turned inside out, so that the seams will cause the sides
to bulge. Thus completed they are called "cells." The cells should be
strung on a cord stretched across the room.
The moths couple as a rule about eight o'clock in the morning. About four
in the afternoon they should be separated by taking them by the wings and
drawing them gently apart. Each female should now be placed by herself in
a cell, which is then closed by a pin as shown in the figure. Here she
will lay her eggs and in due time die. The males may as a rule be thrown
away, but it is wise to keep a few of the more active ones, in case there
should be a superabundance of females the following day.
When the females have finished laying their eggs, which operation
occupies about thirty-six hours, they are ready to be shipped to this
office. The cells, with their inclosed moths and eggs, should be placed
in a strong box of wood or tin, being packed in such a manner that they
will not be crushed, and mailed to the entomologist at the department. By
using the inclosed return penalty slip, payment of postage may be
avoided. The name of the sender should be placed in each box. The moths,
as soon as received, will be examined microscopically, and the eggs of
those which are found to be free from disease will be weighed and paid
for at the rate of $2.50 per ounce of 25 grammes (about 6-7 of an ounce
avoirdupois). Silk culturists are advised not to attempt the production
of eggs unless they are adepts at the industry, and have had at least one
season's experience. We would advise each person desiring to sell, to
send a sample first, with a statement of the quantity offered.
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Dr. Zintgraff of Bonn has taken a phonograph with him to Africa. He
intends to bring home phonograms of the savage dialects which he will
hire the natives to speak into the machine.
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[NATURE.]