A study is made of the asymptotic behavior of the eigenvalues and of expansions in the root vectors of the class of integral operators specified in the title. If some natural conditions, ensuring "regularity" of the asymptotic behavior of the spectrum, are imposed on the kernel, the root vectors form a basis in Lp(0,T)
(1 < p < ∞) and a Riesz basis in L2(0,T).