Measurements of the observed cross sections for e+e−→light hadrons at s=3.773 and 3.650 GeV

Using the data sets of 17.3 pb−1 collected at s=3.773GeV and 6.5 pb−1 collected at s=3.650GeV with the BESII detector at the BEPC collider, we have measured the observed cross sections for 18 exclusive light hadron final states produced in e+e− annihilation at the two energy points.