AbstractShort‐circuited recta of the lubber grasshopper show an initial rapid decline in the short‐circuit current (Isc) over the first 60–90 min in vitro. This is followed by a pseudo steady state during which Iscdeclines slowly and steadily until a true steady state is reached after 4 h. Isccan be stimulated 4–6 fold by the addition of homogenates of corpora cardiaca (CC) or cAMP to the hemocoel‐side of the preparations. This increase in Iscis accompanied by an increase in transepithelial electropotential difference and a large drop in transepithelial resistance. Tracer studies reveal that the initial decline in Iscand its subsequent restoration to high levels is almost entirely due to changes in the active uptake of chloride from the lumen‐side (J LCl→H). Recta maintained in vitro show a graded response to increasing doses of CC homogenates with the threshold occurring near 0.002 gland pair. In all respects these results are qualitatively and quantitatively comparable to those previously reported for the desert locust,Schistocerca gregaria. This represents the first unequivocal demonstration of hormonally‐stimulated chloride transport in an insect other thanSchistocerca, and suggests that this may represent a widespread mechanism for ionic homeostasis in insects. These experiments further lay the groundwork for attempts to purify both the hormone and the chlo