Elementary symmetric polynomials can be thought of as derivative polynomials of En(x) = i=1,...,n xi. Their associated hyperbolicity cones give a natural sequence of relaxations for Rn +. We establish a recursive structure for these cones, namely, that the coordinate projections of these cones are themselves hyperbolicity cones associated with elementary symmetric polynomials. As a consequence of this recursion, we give an alternative characterization of these cones, and give an algebraic characterization for one particular dual cone associated with En-1(x) = 1in j=i xj together with its self-concordant barrier functional.