Morphology of the tibial organs of acrididae: Comparison of subgenual and distal organs in fore-, mid-, and hindlegs of Schistocerca gregaria (Acrididae, Catantopinae) and Locusta migratoria (Acrididae, Oedipodinae).

The structure of the complex tibial organs in the fore-, mid-, and hindlegs of two grasshopper species, Schistocerca gregaria (Acrididae, Catantopinae) and Locusta migratoria (Acrididae, Oedipodinae), is described. In each leg the tibial organs consist of two scolopale organs: the subgenual organ and the distal organ. Both organs are located in the hemolymph channel. The subgenual organ has a sail-like structure, and its scolopidia are oriented perpendicular to the long axis of the leg. The number of scolopidia in the subgenual organs is lower in Locusta migratoria than in Schistocerca gregaria. The scolopidia of the distal organ are clearly spearated from those of the subgenual organ and lie parallel with the long axis of the legs. They insert distally on an attachment plate that lies in the hemolymph channel. The subgenual organs and the distal organs are smaller in the hindlegs than in the fore- and midlegs, and this difference is especially pronounced in Locusta migratoria. The complex tibial organ of Locusta and Schistocerca is very similar in structure and cellular composition with that of Periplaneta (Blattidae). In tettigoniids and gryllids the distal organ is differentiated into an intermediate organ and the crista acoustica. © 1995 Wiley-Liss, Inc. © 1995 Wiley-Liss, Inc.