Abdominal pericardial sinus: a neurohemal site in the tsetse and other cyclorraphan flies.

An ultrastructural study of the heart of the tsetse fly, Glossina morsitans, and of several other species of cyclorraphan flies revealed that the ventral region of the heart of adult flies is supported by a muscular septum not present in the larval stage. The pericardial septum of the adult heart is composed laterally of alary muscles and a central longitudinal muscle that extends the length of the abdominal aorta, whereas the larval heart is supported ventrally only by alary muscles and strands of connective tissue. Thus, unlike the larval stage, and the heart of other insects, the pericardial septum of adult cyclorraphan flies contains a central band of longitudinal muscle, that along with the alary muscle, forms a large pericardial sinus lying between the septum and the heart.

Neuroendocrine modulation of olfactory sensory neuron signal reception via axo-dendritic synapses in the antennae of the mosquito, Aedes aegypti.

An ultrastructural study of the antennae of the yellow fever mosquito, Aedes aegypti, revealed that as in the salt marsh mosquito, Culex salinarius, the first flagellar segment of both sexes of A. aegypti contain neuroendocrine cells. These cells not only extend an axon via the antennal nerve to the antennal lobe of the deutocerebrum, but project collaterals to the periphery of the antennae, where they modulate the antennal sensory neurons by forming synapses with the dendrites of these afferent neurons.