The physical characteristics of biting and stinging insects vary greatly depending on the species. Bed bugs and fleas, for instance, are notable for being tiny and difficult to see, while certain wasp and hornet species can grow as long as 0.5 inches (13 mm) or more. Likewise, the coloration of these pests varies considerably, from the distinctive black and yellow stripes of bees and yellow jackets, to the reddish hue of the fire ant.
Despite their differences, all biting and stinging insects have six legs, a pair of antennae, and a segmented body divided into the head, thorax, and abdomen. Stinging insects also have a stinger, which they use to inject venom.