Like other beetles, tiger beetles have shell-like wing covers (elytra) over the abdomen, and a shieldlike pronotum between the head and elytra. The shape of tiger beetles is distinctive: The elytra sides are parallel, or widen slightly toward the hind end; the pronotum is narrower than the elytra, looking something like a neck, and the bulging eyes make the head wider than the pronotum. The mandibles (mouthparts) are large pincers, and the antennae emerge just above the base of the mandibles. The legs are long and skinny. Color can be black, brown, or green. Many species are iridescent or have bright spots or other color patterns. Their fast-running and fast-flying behavior is another way to identify them.
The larvae, sometimes called doodlebugs, are pale or tan and grublike, with six legs, and have strong pincers at the mouth. There’s usually a hump behind the rather large head. They dig holes down into the ground and rest near the entrance.
Similar species: The larvae of antlions are also (and more commonly) called doodlebugs. They usually live in sandy or dusty substrates and make little conical depressions, which they live at the bottom of, just under a layer of dirt.