Cephalic neuroendocrine system of the buffalo-fly, Lyperosia exigua (De Meijere) (Diptera: Muscidae)

In the adult buffalo-fly, L. exigua three groups of neurosecretory cells are present in each half of the brain; medial and lateral groups in the protocerebrum and ventral group in the tritocerebral region. The cerebral neurosecretory cells are classified as A and B cells. Both the cells are present in the medial, lateral and ventral groups. Histochemically, the neurosecretory material of these cells is composed of neutral mucopolysaccharides and proteins. The A cells are rich in cystine or cysteine amino acids, whereas B cells either lack them or may contain in negligible quantity but are rich in basic amino acids. A single pair or nerves, nervi corporis cardiaci, emerges out of the brain and merges with the recurrent nerve which later on enters the corpus cardiacum and terminates into the hypocerebral ganglion. The corpus cardiacum primarily functions as storage organ for cerebral neurosecretory material and secondarily may also produce its own hormone. The corpus allatum is composed of a single type of cells and some times it appears as syncytial structure. Cerebral neurosecretory material is never found in the corpus allatum.