The spectrum of the dayglow of Venus between 1250 and 1430 A has been measured by the Pioneer Venus Orbiter Ultraviolet Spectrometer. Four bands of the (14,v\) progression in the fourth positive system of carbon monoxide are identified and their excitation mechanism is shown to be fluorescent scattering of the solar Lyamn alpha line. The (14,3) and (14,4) bands at 1317 and 1354 A are blended with the atomic oxygen 1304 and 1356 A lines. The (14,5) band at 1392 A is a prominent unblended spectral feature in the Venus dayglow. This identification provides an additional remote sensing technique to determine the density distribution of carbon monoxide in the upper atmosphere of Venus.