The neurosecretory system of the fruit fly Chaetodacus cucurbitae coq. I. Distribution and description of the neurosecretory cells in the adult fly

Abstract

1. The neurosecretory system of the adult Chætodacus cucurbitae (Trypetidae: Diptera) consists of the cerebral, thoracic and abdominal centres of secretory neurons. 2. The cerebral neurosecretory centres consist of the median and lateral neurosecretory cells of the pars intercerebralis. The cells show characteristic tintorial properties when stained in chrome-hæmatoxylinphloxin and in Azan, recalling the nature of similar cells in other insects. 3. The axons of the median cerebral neurosecretory cells are fairly long, and the nervi corporis cardiaci and corpus cardiacum show granules similar to those observed in the cytoplasm and axons of the cells. 4. The thoracic ganglion shows a more conspicuous set of neuro-secretory cells. They consist of an anterior, lateral anterior, lateral posterior and posterior cell clusters, which in the first three are paired. 5. The single abdominal ganglion contains a few neurosecretory cells also showing characteristic tintorial properties. 6. The nerve emerging from the abdominal ganglion and going to the gut shows blue granules traceable from the neurosecretory cells at the posterior end of the ganglion. 7. Phase contrast observations of the cells show that the neurosecretory cells of the fly have a general structure with prominent cytoplasmic products in the form of dark granules and large and small spheroids and globules. 8. Measurements of the thoracic neurosecretory cells, which forms the larger cells of the system, have been given.