Figure 2 in REVIEW Going underwater: multiple origins and functional morphology of piercing-sucking feeding and tracheal system adaptations in water scavenger beetle larvae (Coleoptera: Hydrophiloidea)

Figure 2. Chewing mandibles, SEM micrograph, dorsal view. A, Derallus sp., first-instar larva. B, Enochrus sp., firstinstar larva. C, Tropisternus sp., second-instar larva. D, Hydrophilus (Dibolocelus) palpalis Brullé, 1837, first-instar larva. E, Dactylosternum cacti (LeConte, 1855), third-instar larva. F, Cercyon quisquilius (Linnaeus, 1761), third-instar larva. Abbreviations: rc1, first retinaculum; rc2, second retinaculum; rc3, third retinaculum.