Abstract: Certain novel N-(heteroarylalkyl)alkanediamine derivatives have provided unexpected insecticidal and acaricidal activity. These compounds are represented by formula I: wherein Ar, a, b, c, T, W, Y R, Rf, Rg, Rh, Ri, Rj, Rk, Rm, Rn, and R are fully described herein. In addition, compositions comprising an insecticidally effective amount of at least one compound of formula I, and optionally, an effective amount of at least one of a second compound, with at least one insecticidally compatible carrier are also disclosed; along with methods of controlling insects comprising applying said compositions to a locus where insects are present or are expected to be present.