Expression of Trlhs.PG using heat shock at 37oC fails to rescue the lethality of Trl62, TrlR85 or TrlR67 homozygotes or of Trl62/TrlR85, Trl62/TrlR67 or Trl62/Trl13C flies. Expression of Trlhs.PG using heat shock at 37oC slightly rescues the lethality of Trl13C homozygotes; 0.41% homozygotes out of the expected 33% of total progeny are recovered. Expression of Trlhs.PG using heat shock at 37oC slightly rescues the lethality of Trl13C/TrlR67 flies, approximately 5% of the expected progeny are produced. Trl13C/Trl13C and Trl13C/TrlR67 rescued adults can survive at room temperature for no longer than 3 days and are sterile. Expression of Trlhs.PG using heat shock at 37oC slightly shifts the lethal phase of Trl62/Trl62 homozygotes; the percentage of homozygous pupae is increased to 12% with heat shock treatment compared to 7% without heat shock.