THE ENDOSKELETAL SALIVARY PUMPING APPARATUS IN REPRESENTATIVE BELOSTOMATIDAE (HETEROPTERA)

Abstract

The salivary pumping apparatus in representatives of the aquatic family Belostomatidae (Insecta) is discussed. Observations were based upon dissections of adult Lethocerus and histological serial sections through the heads of nymphal Belostoma. The simple, two-layered salivary pump, its afferent and efferent openings, and the paired afferent and single efferent ducts are described. Also discussed are the mechanism of the pumping apparatus and its relationship to other endoskeletal structures. The pump and efferent duct are hypopharyngeal specializations in the Heteroptera, the efferent duct originating as a groove in the floor of the hypopharyngeal lobe. In Belostomatidae this groove is closed anteriorly, but caudally it remains open ventrally.