A redescription of Microtrombidium pusillum (Hermann, 1804) (Acari : Parasitengona : Microtrombidiidae) with notes on taxonomy and biology

The adult and deutonymph of Microtrombidium pusillum (Hermann, 1804) are re described; the heteromorphic larva reared in laboratory is described for th e first time. The taxonomic status of the genus is revised; diagnoses of al l active instars are provided. The neotype is designated basing on the fema le from which larvae have been obtained by experimental rearing. Megophthro mbium Mullen and Vercammen-Grandjean, 1978, Phlebotrombium Fain and Baker, 1993 and Crinitrombium Southcott, 1994 are considered subjective junior syn onyms of Microtrombidium Haller, 1882. Larvae hitherto described as Microtr ombidium do not belong to this genus; their generic status is discussed. Al exothrombidium gen. nov. based on Microtrombidium baerti Fain and Grootaert , 1993 as type species and Parawillungella pen. nov. based on Microthrombid ium nitidum Southcott, 1994 as type species are described. The phenology, l ife cycle and parasitism of M. T. pusillum are discussed and compared with adequate data for other Microtrombidiiae.