The main distant receptor organ of H. criceti, situated on the tarsus of each first leg, was studied by scanning and transmitting electron microscopy. The organ contains 6 types of sensilla, including 4 distant ones (two types of olfactory sensilla, differing in wall thickness, and 2 types of probable chemo-thermosensitive sensilla, possessing different double-walled hairs), and also taste organs of common structure and microchaeta. Cilia of all the sensilla contain 13 pairs of peripheral fibers. Comparative analysis of fine structure of distant sensilla in bloodsucking insects, ticks and mites made it possible to show, that blood-sucking gamasids and ticks possess similar number of homologous sensillar types, that formed on a common ground as the specific adaptation to blood-sucking.