Benito Mussolini had this less-than-conciliatory policy: “Let us have a dagger between our teeth, a bomb in our hands, and an infinite scorn in our hearts.”

Ouch. Someone needs to lighten up.

But Mussolini’s animosity might have been at least somewhat understandable, if the dagger between his teeth was an American dagger mothcaterpillar. These hairy caterpillars, which are yellow when young and white and black in their later stages, could cause some problems for Benito if he chose to put one in his mouth, or even in his hand.

The white furry American dagger moth caterpillar, with its black pencil tufts of hair on its first, third, and eighth abdominal segments, is one of the stinging caterpillars that are currently crawling around. Another common cantankerous caterpillar that is also out and about in the fall is the hickory tussock moth caterpillar. This variety also has long white hairs, but has lots of black coloring on its body.

Caterpillars don’t sting in the traditional sense of the word, since they don’t have a stinger, as bees or wasps do. It is their hair, not a stinger, that can cause harm to those with sensitive skin. The hairs (called setae) of certain caterpillars are actually a weapon, their defense against enemies — and against others who just accidentally touch them. These setae are hollow and are connected to small poison glands whose contents when released can cause skin irritation.

Although I am not a doctor, nor do I play one on television, I do know of a few recommended treatments for those afflicted with this type of caterpillar dermatitis. First, be sure to remove the hairs or spines from your skin. Tape can be used to pull them off easily. Then wash the affected area thoroughly and apply ice. A poultice made from baking soda can stop the itch , as can topical anti-itch creams. Aspirin doesn’t often help, but an antihistamine has been recommended in severe cases.

If the caterpillar survives your wrath after a rash, it will grow to go into its next cycle of life. Before these caterpillars pupate, they will eat voraciously. American dagger moth caterpillars feed on alder, ash, elm, hickory, maple, oak, poplar, willows and other tree varieties, as they are not picky. The hickory tussock, on the other hand (and watch out for the rash, if the animal is on your otherhand!) prefers nut trees, such as hickory, walnut and butternut, and often is found feeding in groups. These potent packs of predators will easily skeletonize leaves, so just their lacy vein framework remains.

Both caterpillars will overwinter in cocoons (chrysalises are only for butterflies). Next spring will bring delicate moths from their off-season seclusion. Small moths result from both of these caterpillars; hickory tussock moths are brown and white, while dagger moths are grey and white.

Like Shakespeare’s Macbeth, you may find yourself wondering when you are outside, “Is this a dagger which I see before me?” If it is, use caution when examining either of these two caterpillar varieties, and read between the lines. The potential for danger is right there in black and white.

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.