Bordered Wedge-shaped Beetle

Macrosiagon limbata is a species of wedge-shaped beetle in the family Ripiphoridae. They are found across the Eastern United States, Southeastern Canada and Central America. It is likely that their range extends into South America but this currently remains unknown.

Macrosiagon limbata was first discovered in 1781 by the famous zoologist Johan Christian Fabricius. Coleopterans in the genus Macrosiagon are internal parasites of other insects at some point during their lifecycle. They go through a form of hypermetamorphosis, in which the larva goes through multiple stages of morphologically distinct instars. The female deposits eggs on flowers visited by bees and other hymenopterans. Larva of Macrosiagon limbata have been reported as parasites of the wasp family Crabronidae. The first larval instar is a planidum, an active larva that can climb on a host hymenopteran. They are then transported to the host's nest, where they act as parasitoids. The following instars don't have legs, and feed on larvae or stored pollen and nectar supplies.