Lesson XCIV

The Firefly

Leading thought—When the firefly wishes to make a light, it can produce one that, if we knew how to make, would greatly reduce the price of artificial light; for the light made by fireflies and other creatures, requires less energy than any other light known.

Method—After the outdoor observations have been made, collect some of these beetles in the evening with a sweep net; place them under a glass jar or tumbler, so that their light can be studied at close range. The next day give the observation lesson on the insects.

Observations—1. At what time of year do you see fireflies? Do they begin to lighten before it is dark? Do you see them high in the air or near the ground? Is the flash they give short, or long enough to make a streak of light? Do you see them on cold and windy nights or on warm, still, damp evenings? Make a note of the hour when you see the first one flash in an evening.

2. Catch a few fireflies in the night; put them under a glass jar. Can you see the light when they are not flashing? What color is it? When they make the flash can you see the outline of the “firefly lamp?” Watch closely and see if you think the flashing is a matter of will on the part of the firefly. Do you think the firefly is signaling to his mate when he flashes?

3. Study the firefly in daylight. Is it a fly or is it a beetle? What color is it above? When you look squarely down upon it, can you see its head and eyes?

4. Are the firefly’s legs long or short? When a beetle has short legs is it a sign that it usually walks, runs or flies?

5. Describe the antennæ. Are they in constant motion? What service do you think the firefly’s antennæ perform for it?

6. Lift one of the wing-covers carefully. What do you find beneath it? Does the beetle use its wing-covers to beat the air and help it during flight? How does the beetle hold its wing-covers when flying?

7. Turn the beetle on its back. Can you see the part of the body that flashes? What color is it?

8. Do you know the life history of the firefly? What is it like in its earlier stages? Where does it live? Does it have the power of making light when it is in the larval stage?

“There, in warm August gloaming,
With quick silent brightenings,
From meadow-lands roaming,
The firefly twinkles
His fitful heat-lightnings.”

—Lowell