(1) Rostral parts of the wing (prepatagium, alula) were represented rostrally (C12, C13) and caudal parts (secondaries) caudally (C14).
(2) The organ consists of a proximal scolopidial region and a distal strand, which attaches peripherally to the membraneous cuticle ventral to the hindwing alula.
(3) Distinct immunoreactivity was shown in the many Dogiel type 1 neurons, characterized by short broad processes (winglets or alulae) and one long axon-like process, as well as a few type 2, characterized by several tapering processes, and type 3 neurons, characterized by dendrite-like processes.
(4) The atympanate organ possesses three sensory cell bodies and three scolopales, and is anchored peripherally via an attachment strand to the undifferentiated membranous region underlying the hindwing alula, which corresponds to the tympanal region of the noctuoid metathorax.