The alternation of a parasitic larva and predatory postlarval instars as well as the colonization of aquatic and terrestrial habitats make Parasitengona one of the most diverse taxa within the ‘Acari’. This is not only expressed in strong morphological differences between larvae and postlarval instars, but also in a high diversity of ectomorphological characters of larvae in the various subgroups. We hereby report the first case of hitherto unknown microtrombidiid larva with a special kind of reinforced integument within the opisthosoma. The structure and function of this armor will be analyzed and compared to adequate features in other parasitengone mites, and particularly Microtrombidiidae. The phylogenetic position of the species within Microtrombidiidae is discussed. The active postlarval forms of microtrombidiid mites were sampled in Alaotra-Mangoro Region, in central- eastern Madagascar. The larvae were obtained from field-collected, oviferous females. Ectomorphology of active postlarval forms and of larvae, randomly selected from the progeny of various females, was investigated with light microscopy and, in the case of larvae – also with scanning electron microscopy. Few EtOH-preserved specimens were devoted to molecular examination. A Maximum Likelihood (ML) tree based on the COI dataset was constructed to reveal the putative relationships of the examined genus and species with other microtrombidiid genera. Based on the characters examined in active postlarval forms the species was assigned to the genus Coccothrombium, hitherto known exclusively from adults and deutonymphs. Behind the scutum, the larva exhibits a net-like, cuticular reinforcement of the opisthosomal region, which has not previously been observed in other microtrombidiid larvae or in larvae of Parasitengona in general. Protection against predators during the phase of host searching is most likely the adaptive value of this evolutionary novelty. This advantage is paid for with a decrease of growth capacity in the larval instar. Alternative strategies to avoid predation are discussed by comparison to larvae of other Parasitengona taxa.