Sequence encoding the GAL4 driver has been inserted into the attP site in the TI{TI}Dsec\Df-Or85cb-RFP sequence cassette carried on the Dsec\Df(?)Or85cb-RFP chromosome, allowing expression of the GAL4 driver under the control of the endogenous regulatory sequences of Dsec\Or85c and/or Dsec\Or85b. The chromosome still carries (inherited from the Dsec\Df(?)Or85cb-RFP progenitor chromosome): i. a deletion of most of the Dsec\Or85c gene and part of Dsec\Or85b exon 1, and ii. a loxP cassette containing the Disc\RFPDsRed(T1).3xP3.cHa marker.