Why are ladybugs beetles rather than true bugs?

Ladybugs are classified as beetles rather than true bugs because they belong to the order Coleoptera, whereas true bugs belong to the order Hemiptera.12

The distinction is based on several biological differences:

• Wing Structure: Beetles have two pairs of wings, with the outer pair modified into stiff, protective covers called elytra that meet in a straight line down the back. True bugs have forewings that are thickened only at the base, with membranous tips that overlap when at rest.134
• Development: Beetles are holometabolous, meaning they undergo complete metamorphosis, including egg, larva, pupa, and adult stages. True bugs are hemimetabolous, undergoing incomplete metamorphosis where they hatch as nymphs that resemble smaller versions of the adult.1
• Feeding: Beetles possess mouthparts adapted for chewing and gnawing. In contrast, true bugs have specialized mouthparts, or stylets, designed for piercing and sucking plant or animal juices.14

While both are members of the class Insecta, these fundamental differences in anatomy and life cycle clearly separate them into distinct taxonomic groups.12