Type II Pyrethroid exhibited its potential against transgenic forms of Drosophila melanogaster. The intrastrain crosses and respective observations with regard to genetic expression on the imaginal disc have revealed the potentiality of the experimental compound alphamethrin on both transgenic flies, wingless lac Z and engrailed lac Z . The reduction in wing size in both the forms (wingless lac Z and engrailed lac Z) is also an outcome of engrailed gene which acts as a pleotropic gene governing different functions in different parts of Drosophila. The differential expression of gene in the two transgenic forms reflect differential interaction in terms of reduced response of pyrethroid with the concerned gene.