The shear-induced microstructure of a shear-induced phase separating (SIPS) wormlike micellar solution is measured by combining small-angle neutron scattering with a shear cell capable of gap-resolved measurement in the 1-2 (velocity-velocity gradient) plane. Quantitative results show evidence for shear-induced microphase separation accompanied by shear banding. The results suggest both concentration fluctuations and gradients in segmental alignment occurring during SIPS.