Prodorsal Trichobothria

Many acariform mites have 1-2 pairs of well developed bothridial sensilla on the prodorsum.  The cup-like bases (bothridia) of these structures resemble a stigmatal opening and were once thought to be respiratory organs, but their primary function appears to be sensing air currents.  The sensilla come in various shapes from setiform to pectinate to plumose to club-shaped.  They are variously called pseudostigmatic organs, trichobothria, or bothridial sensilla.