Beetle larva living on a spider-hunting wasp. Differential interference contrast (DIC) micrograph of a beetle larva living on the mouthparts of a spider-hunting wasp. The beetle is a 1st instar larva of either a rhipiphorid (an unusual family of beetles), or possibly a twisted-wing fly (Strepsiptera). Both Rhipiphorids and Strepsiptera are partially parasitoids of bees or wasps, though they are also known to attack other hosts. The tiny 1st instar larvae are known as triungulins, and board adult bees or wasps (Hymenoptera), in order to be brought back to their nests. Once there, the triungulin attacks either the larvae of the bee or wasp as a parasitoid, or the host of the wasp. Length of beetle larva is 0.1 mm.