Spreading Butterflies

Moths and butterflies look better and are easier to identify if their wings are spread properly. A spreading board is used to do this. Adjustable spreading boards for use with different sized butterflies can be bought from biological supply houses. The slots in the cover of the styrofoam box you might have bought for 4-H Entomology Unit I can also be used for spreading. If you don't have either of these, you can make a spreading board according to the instructions given in the Optional Exercises.

Put an insect pin through the center of the thorax of a freshly killed butterfly. If the insect has dried, use a relaxing jar to soften it. (See Optional Exercises for instructions on making a relaxing jar.) One-fourth inch of the pin should be exposed above the thorax. Make sure the insect does not tip from side to side or from front to back on the pin.

Push the pin straight down in the center of the slot of your pinning board until the outstretched wings are just level with the surface of the pinning board.

Insert an insect pin lightly in each front wing near the front margin and just behind one of the heavy wing veins. Move the front wings forward gently until the hind margins of the front wings are in a straight line, at right angles to the body.

With a pin placed behind a heavy vein in the hind wing, move each hind wing forward until the gap between the front wing and hind wing is closed to just a notch, as shown on the right side of the illustration below.

Cut some narrow strips of paper and lay them over the wings. Pin them in place as shown. Remove the other pins that are through the wings. The pins holding the paper strips in place should not go through the wings but should be close to them to keep enough pressure on the wings to prevent their slipping out of place. Some entomologists use transparent paper so they can see if the wings have slipped out of place while the specimen is drying. Paper that is too thin will not give enough pressure on the wings. If the abdomen tends to sag, it can be propped up with pins until it dries. You can also use pins to keep the antennae in place while the specimen dries. Depending on the moisture in the air, the specimen should remain on the board from four to eight days.