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Transcription
four strips of light card of the same length but a quarter
of an inch more than wide enough to cover the wings
of one side of the largest specimen the board is to
hold. When spreading a large mixed lot, it will save
time if you make a quantity of strips of assorted sizes
and keep them in readiness.
Lay out the pins, papers, and mounting tools where
you can easily reach them, together with the relaxing
box holding the insects. During the spreading
operations, the board lies with one end toward the
spreader, and the work progresses from the middle of
the board toward that nearer end. When half of the
board is filled, the position of the ends is reversed
and the process repeated. Some workers raise the further
end of the board by resting it on a book or shallow
box.
Along each side of the central groove place two
guide strips with their inner ends overlapping about
three-eights of an inch and fastened at the middle of
the board with a glass-headed pin. This overlap
appears in fig. 10. The outer ends of these strips will
extend for a short distance beyond the ends of the
board.
With the pointed tweezers, remove a specimen from
the relaxing box, holding it firmly by the thorax.
Blow upon it gently from behind. If the wings
flutter slightly, the specimen is soft enough to spread.
Lay it upon the palm of your left hand, with the wings
away from you and the head toward your right. With
the points of the forceps parallel to the insect's body,
seize it just under the bases of the wings, and pinch.
This will cause the wings to open enough for you to
see where to insert the pin. Use a steel insect pin as
large in diameter as the specimen can accommodate
without distortion. It will serve as a handle for the
insect, which ought never to be touched with the
fingers, and which, when dry, will be extremely
brittle. Hold the pin in the left hand, and pass it
directly through the thorax, between the wings, from
top to bottom and at right angles to the length of the
body. It should protrude about 3/8" above the back.
Holding the point of the pin in the left hand, take
the pin forceps in the right and, sliding them between
the wings, grasp the top of the pin. Holding the
specimen in this manner, body parallel to the groove
and head away from you, push the point of the pin
straight down through the cork strip at the bottom of
the groove until it strikes the wooden bar beneath. So
that the spreading of the wings may not be obstructed
by the pins holding the guide strips, insert the first
insect pin about an inch away from them. The body
of the insect, with the legs folded close against it,
should lie neatly in the middle of the groove. If the
upper edges of the boards do not strike just below the
bases of the wings, move the specimen up or down
upon its pin until they do.
Lifting the right guide strip by its free end, slide it
between the wings and use it to pull the wings of the
right side down against the board. Put a pin through
the strip just back of the wings to hold them out of the
way while you work on the other side. This also may
be seen in fig. 10.
Depress the wings of the left side by means of the
left guide strip, kept taut between the thumb and fore-
finger, and held down by the third finger of the left
hand. Taking one of the spreading needles in the
right hand, use it to pull the left forewing forward
until its rear margin is at right angles to the length
of the body. This can be done without tearing the wing
membrane if the needle point is inserted just back of
one of the heavy veins near the front margin of the
wing close to the guide strip. When the wing is in
position, drive the needle through the membrane and
into the board, to keep the wing from slipping back
during the following operations.
If the pull on the wing causes the body to pivot on
its pin, a second insect pin placed close against the
body just in front of the right forewing and driven
securely into the bottom of the groove should over-
come the difficulty. Fig. 10 shows this restraining pin
in place. The position of the antennae under the
guide strips may also be seen in fig. 10.
Using a second spreading needle behind a strong
vein, pull the left hind wing forward and fasten it in
place, securing it further by a pin through the guide
strip just back of its rear edge. The exact relative
position of the fore and hind wings is a matter of
controversy. Tradition demands that the margins of
the two form a smooth continuous outline, but as so
great an overlap conceals the often interesting charac-
ters near the upper front margin of the hind wing, the
Fig. 10. Butterfly half spread.