Concept:A long coiled proboscis used for sucking nectar is characteristic of butterflies.Explanation:In butterflies, the maxillae are elongated and joined to form a coiled tube called the proboscis.This structure is adapted for sucking nectar from flowers.Houseflies have sponging mouthparts, mosquitoes have piercing-sucking mouthparts, and grasshoppers have chewing mouthparts.Answer:B. butterfly