Peripheral neurosecretory cells in some Lepidoptera

Abstract

A segmental series of peripheral neurosecretory cells was found in larvae of some Lepidoptera. They occur in the thoracic segments and in the first eight abdominal segments, towards the distal end of the transverse nerves. In the thorax, and in abdominal segments 1, 2, and 8 there is usually a single cell, but in abdominal segments 3–7 there are 2–14 cells. The latter have the appearance of small ganglia and lie on the aliform muscles where the transverse nerve divides to innervate the individual muscle fibres. All of the peripheral neurosecretory cells appear to produce the same secretion, some of which is discharged through the transverse nerves and released at the proximal neurohaemal dilations. Other fibers extend distad from the cell bodies and may supply the aliform muscles.