Let G be a connected,
reductive p-adic group and let Ge denote the set of regular elliptic elements of G. Let
π be an irreducible, tempered representation of G with character Θπ, and write Θπe
for the restriction of Θπ to Ge. We say π is elliptic if Θπe is non-zero. In this paper
we will characterize the elliptic representations for the p-adic groups Sp(2n) and
SO(n). We will show for Sp(2n) and SO(2n + 1) that every irreducible, tempered
representation is either elliptic or can be irreducibly induced from an elliptic
representation. We will then show that this fails for the groups SO(2n). In this case
there are irreducible tempered representations which cannot be irreducibly induced
and are not elliptic.