The Elateridae, or click beetles as they are commonly called, constitute a comparatively large family. Leng's catalog lists over 600 species for North America, north of Mexico. While a few of our adult Elaterids reach the length of nearly two inches, the majority of our common species would range around l/2 inch in length, and occasionally species are not over 1/10 inch long. They are elongate in form, tapering more or less at each end, thus somewhat resembling the Buprestidae but are more loosely jointed between the thorax and abdomen. Many are dull brown or blackish in color, and are covered with a fine pubescence. They are found beneath bark, logs, stones, at the roots and on the foliage of various plants. The elasticity of the Elateridae gives the members of this family the power to leap into the air when placed on their backs. The actual movement is directly due to these facts: first, the prosternum is prolonged into a spine which extends into a groove in the mesosternum; and second, there is a loose articulation between the prothorax and the mesothorax so that the former can freely move up and down. As a preparation for the leap, the beetle bends its body so as to bring the prosternal spine nearly out of the groove in the mesosternum. Then by relaxing the muscles, the body straightens and allows the prosternal spine to be forcefully plunged back into the groove. This violent blow given to the mesothorax causes the base of the elytra to strike the supporting surface with force; thus the insect is hurled upward for several inches. The purpose of this interesting movement seems to be twofold: protection from enemies and to turn the beetle back on its feet.
Proceedings of the Iowa Academy of Science
©1943 Iowa Academy of Science, Inc.
Owen, Billy and Jaques, H. E.
"A Preliminary List of the Elateridea of Iowa,"
Proceedings of the Iowa Academy of Science, 50(1), 341-344.
Available at: https://scholarworks.uni.edu/pias/vol50/iss1/34