Let S denote a Banach space
over the real numbers. Let A denote the infinitesimal generator of a strongly
continuous semigroup T of bounded linear transformations on S. It is known that the
Riemann integral ∫abT(x)pdx is in the domain of A (denoted by D(A)) for each p in
S and each nonnegative number interval [a,b]. This paper develops sufficient
conditions on nonnegative continuous functions f and on elements p in S in order
that the Riemann integral ∫abT(f(x))pdx be an element of the domain of
A.