  Let $\tilde{G}$ be a symplectic or even orthogonal group over a p-adic field
$F$, and $M$ the Levi factor of a maximal parabolic subgroup of $\tilde{G}$.
Suppose that $M$ has the shape of three blocks of the same size. Let $\pi$ be a
supercuspidal representation of $M$. In this paper we give a simple explicit
expression for the residue of the standard intertwining operator for the
parabolic induction of $\pi$ from $M$ to $G$.
