The transposable element Mi{ET1}MB04184 line (FlyBase ID:FBti0100486 ) is homozygous lethal but the lethality is not due to its insertion point.
It complements (F1 with straight wings) with the deficiency Df(2R)BSC281 (FlyBase ID: FBab0045044) that uncovers the transposon insertion point.