From the Futon Critic,
As FOX shuffles the schedule around for Spring...
Bones will return a little bit earlier than expected on April 2 as FOX moves Bones to Mondays at 8PM followed by House at 9PM as House heads to its series finale. Bones will be pre-empted (yeah, I know you thought there wouldn't be any more interruptions ) on May 21 as FOX airs a House retrospective on May 21 at 8PM.
Here's the link to the article: FOX's Spring Schedule