Is Trombidium Holosericeum the Parent of Leptus Autumnalis?

The question whether Trombidium holoserlceum Linn6, is the parent of Leptus autumnalis Latre'flle, (Leptus autumnalis Shaw) does not affect our work o n tsutsugamushi directly. B u t indirectly, in the invest igat ion of the life cycle of the tsutsugamushi, the carrier of tsutsugamushi disease, the question is of importance, because the tsutsugamushi, or akamushi, is almost identical with the European Leptus autumnalis. From our observations and from a s tudy of the l i terature we cannot accept the view tha t Trombidium holosericeum is the pa ren t of Leptus autumnalis.