The escape response of cockroaches, Periplaneta americana, can be triggered by abrupt tactile stimulation of the antennae. Several descending mechanosensory interneurons (DMIs) are believed to be involved in antennal touch-evoked escape. In particular, DMIa-1 is a cell of the protocerebrum that responds to antennal touch and has a crossed axon that descends to the thoracic ganglia (Ye and Comer 1996). Deflection of one antenna elicits a contraversively directed escape turn and then a run. It is not known what antennal receptors activate the DMIs and provide the crucial trigger for escape. It is clear that the receptor(s) is located in or on the basal antennal segments (SFN abstract Baba and Comer 2003), but many types of receptors are located there. We have selectively ablated receptors at the antennal base and then correlated the effects on the behavior with effects on activation of DMIs. Removal of hair plates at the antennal base had no significant impact on antennal touch-evoked escape. However, remova...