A 6.5kb EcoRI fragment of the ctregulatory region fused to a minimal Hsp70 promoter drives expressionof EcollacZ in embryonic, larval, and adult tissues. In the embryo, EcollacZexpression is seen in tracheal histoblasts, anterior spiracles, and weaklyin the Malpighian tubules. In the larva, the ventral ganglion expressesEcollacZ, while in the adult, EcollacZ is found in simple external sensoryorgans (with the exception of the chemo- and mechanoreceptors on the wingmargin).