  We compare UV spectra of the recent soft X-ray transients XTE J1118+480 and
XTE J1859+226. The emission line strengths in XTE J1118+480 strongly suggest
that the accreting material has been CNO processed. We show that this system
must have come into contact with a secondary star of about 1.5 solar masses,
and an orbital period ~15hr, very close to the bifurcation value at which
nuclear and angular momentum loss timescales are similar. Subsequent evolution
to the current period of 4.1 hr was driven by angular momentum loss. In passing
through a period of 7.75 hr the secondary star would have shown essentially
normal surface abundances. XTE J1118+480 could thus represent a slightly later
evolutionary stage of A0620-00. We briefly discuss the broad Ly alpha
absorption wings in XTE J1118+480.
