There are three recessive mutations on the X chromosome of Drosophila, called Huey (h), Dewey (d), and Louie (I).
In order to map these mutations,
you cross flies that are true-breeding for huey,
to flies that are dewey Iauie.
The F1 females are all wild type, and they are crossed to wild type males.
The F2 females are all wild type, but the F2 males consist ofthe following phenotypic classes: