10.  Fireflies
Fireflies, or lightning bugs, are actually beetles. These insects are well known for their ability to produce light by means of a luminescent organ near the abdomen. Both the male and female fireflies occurring east of the Rockies can fly and blink their light organs. In the West the adult female glows but cannot fly, and the male flies but does not produce light. Larvae of some fireflies also produce light and are called glowworms. Adult fireflies are soft-bodied beetles ¼ to ¾ inch in length. Their head is concealed from above by a hard covering. All larvae and some adults are beneficial, predaceous insects that feed at night on other insects and small slugs and snails. The larvae live in moist places among debris on the ground or on low-growing herbs and grasses. The adult fireflies use their flashing lights as signals in courting. They become active at dusk, with the number of flashes increasing as the night gets darker, and continuing well into the night.