  In this note we give a self-contained proof of the following classification
(up to conjugation) of subgroups of the general symplectic group of dimension n
over a finite field of characteristic l, for l at least 5, which can be derived
from work of Kantor: G is either reducible, symplectically imprimitive or it
contains Sp(n, l). This result is for instance useful for proving "big image"
results for symplectic Galois representations.
