small air-breathing arthropod
"The gardener carefully swept away the insect, a tiny air-breathing arthropod that had been chewing on her rose leaves."
An arthropod (in the Insecta class) characterized by six legs, up to four wings, and a chitinous exoskeleton.
"The magnifying glass revealed that the tiny creature crawling on the leaf was an insect, identifiable by its three pairs of jointed legs and hard outer shell."