Final answer:
Beetles, part of the Coleoptera order, have the most protected membranous wings, shielded by a hardened pair of front wings called elytra.
Step-by-step explanation:
The insect order with the most protection for its membranous wings is the beetles. Beetles exhibit a specialized pair of hard front wings called elytra, which serve as a protective shield for the delicate hind wings when not in flight. This protection is particularly effective at safeguarding the membranous flight wings from physical damage and desiccation.
Beetles belong to the order Coleoptera, which is distinguished by these hardened wing covers that meet in a straight line down the back when the beetle is at rest. The elytra do not aid in flight but are essential for the protection and survival of these insects, demonstrating an evolutionary advantage that has contributed to the success and diversity of the group.