Butterflies taste with sensitive taste organs on the soles of their feet, not with their tongues.  Butterflies feed on the nectar of flowers and other plant liquids.  A butterfly cannot bite or chew.  It has a long coiled tube, called a “proboscis,” which it uses like a straw to suck liquids into its mouth.

When the butterfly lands on a flower, its feet taste the flower’s sweetness. When a butterfly finds nectar in a flower, it uncoils its long, hollow proboscis and sucks in the liquid.  The proboscis coils back up out of the way when the butterfly is finished.–Dick Rogers