An Easthampton man accused of killing his girlfriend has been ordered by the court to deliver a DNA sample.  Ryan Welch's lawyer argued police already had some of his blood.  Prosecutors countered the sample was needed to compare with evidence gathered at the crime scene.  They also wanted to preempt any argument that blood taken at the hospital after Welch tried to kill himself was mislabeled.  Welch is charged with stabbing Jessica Pripstein to death in her Easthampton apartment.