House Speaker Thomas P. (Tip) O'Neill Jr. has sent a sharp note to 44 House Democrats who deserted the party on an important procedural vote last month.

Rep. John Ashbrook (R-Ohio) had offered an amendment to the Treasury Department appropriation bill forbidding the Internal Revenue Service from withdrawing tax-exempt status from private schools found to have discrimated against minorities. The presiding officer ruled Ashbrook's amendment out of order as legislation on an appropriation bill. Ashbrook appealed the ruling forcing was upheld but there was a large defection for a procedural vote, as distinguished from a vote on substance.

The Senate often votes on appeals from rulings of the chair, but it is almost unheard of in the House. O'Neill wrote to the Democratic defectors, who included two committee chairman -- Charles Bennett (D-Fla.) of ethics and Jamie Whitten (D-Miss.) of Appropriations -- that until 1968 there had not been an appeal from a ruling of the House's presiding officer in 30 years. In the past 11 years there were four plus three this summer alone.

O'Neill said a vote on a procedural motion in the House Compares to a vote of confidence in a parliamentary system and that in those countries if a vote to sustain the chair had failed the government would fall.

O'Neill wrote that at recent meetings of the Democratic whips and the House Democratic Steering Committee there has been considerable discussion of Democrats defecting on procuedural matters. At least one member called for disciplinary, action such as taking awy committee chairmanships, he said.

But O'Neill said he believed the best course was to call the situation to members' attention and ask them to "support the orderly process" in the future.