Recovery of Unengorged Larval Trombiculid Mites (Acarina) from Ground Holes

PREVIOUSLY it was found possible to identify the natural habitats of a limited number of species of larval trombiculid mites (chiggers) in Malaysia by recovering them from the ground on black ‘Formica’ plates 1 . In such habitats as were found, it was possible to observe with the naked eye chiggers both singly and in clusters. Only two species of chiggers have so far been subjected to intensive investigation using this recovery technique and both were vectors of scrub typhus, Leptotrombidium (Leptotrombidium) deliense (Walch, 1922) and L. (L.) akamushi (Brumpt, 1910). In the few localities studied by this means, the former was found in lalang grassland ( Imperata cylindrica ) and the latter on ground leaf-litter of secondary forest galleries 2 . In the course of current investigations of scrub typhus in the primary and secondary forests of Malaysia, we have collected a number of species of larval trombiculids—previously found only on small forest mammals—by insertion of a flat strip of black ‘Formica’ into ground holes.