The name 'Spitfire' is often given to two common species of Australian insect larvae.

One is a Caterpillar : Doratifera vulnerans, which everts stinging hairs when disturbed. It does not actually spit anything, but the sting from the hairs hurts like a burn does.

The other is not a true Caterpillar, but is the larva of a wasp belonging to the species Perga dorsalis. When disturbed, this larva exudes a noxious liquid from the mouth, but it cannot eject it.

No Australian Caterpillars can actually spit.

Note that the Processionary Caterpillar is different from those called Spitfires, but it has hairs that cause a burning-like inflamation of the skin of some people if they touch them.