The 1st cross produced eggs, but they did not hatch or become pupae. In all of the 10 vials, eggs were observed, but no pupae. On the other hand, the 2nd cross did not produce any eggs. (The first trial was kept up for 10 days. After 10 days, a new trial began from the same stock. ) Control and the other two crosses produced eggs and hatched new flies.

The same crosses were repeated to ensure the lethality. In the second trial, ‘T4/T5xWTB’ cross produced eggs and pupae. But there is still the possibility that the T4/T5xWTB is also a lethal crossing. ‘T4/T5xTNTE’ cross again produced only eggs but no pupae. The other two crosses produced pupae again and became dark, but haven’t hatched yet. The second attempt is 10 days old.