Virginia House Speaker John Warren Cooke today gave the Northern Virginia legislative delegation fewer than the four seats it normally receives on 10 of the House of Delegates' 13 major committees.

Several of the legislators from the Washington suburbs said their underrepresentation on the budget-writing House Appropriations Committee, and the Courts of Justice Committee, which among other things considers appointments of judges, was particularly galling.

While there is no House rule that two members from each of the state's 10 congressional districts be assigned to each 20-member committee, tradition has led legislators generally to expect such representation. There are two congressional districts in Northern Virginia.

"It's absolutely incredible," said Del. Raymond E. Vickery (D-Fairfax). "I'm at a loss to understand how the speaker could show this hostility to one area."

Committee assignments are made solely by Cooke. He earned notice nine years ago when he opened up the selection process after decades of Byrd organization domination under which rural legislators were granted far more desirable and powerful assignments than urban or liberal ones. Under the current process, House members let Cooke know what committees they would like to be on and discreet lobbying is done through intermediaries close to Cooke. Then Cooke makes the assignments.

Cooke could not be reached for comment on his appointments.

This time, Northern Virginia has four or more representatives on three major committees -- counties, cities and towns, privileges and elections, and agriculture.

Vickery speculated that some of the under-representation might be due to the defeat of former Majority Leader James M. Thomson of Alexandria, who was close to Cooke. "I wonder what effect the loss of Jim Thomson had on the lobbying effort," Vickery said.

Committees are important because they are the first stop for proposed legislation. A majority of committee members must vote to "report" a bill before it can be sent to the full House for consideration. Thus, the composition of a committee is significant.

For example, on the Appropriations Committee, of which Thomson would have been chairman if he had not been defeated by Del. Gary R. Myers (R-Alexandria), there are now only three Northern Virginians -- Del. Dorothy S. McDiarmid (D-Fairfax and Dels. Vincent F. Callahan Jr. and Warren E. Barry, both Fairfax Republicans. Barry is a new appointee.

he Appropriations Committee decides how much money to propose spending on such things as Metro construction and community colleges. Del. Richard R.G. Hobson (DAlexandria) said Northern Virginia legislators probably would pool their aides' talents and assign one to monitor the committee at all times. He noted there is now no one from Alexandria or Arlington on the committee.

Another serious loss for Northern Virginia was on the Courts of Justice Committee, which now has only Hobson and freshman Del. James Almand (D-Arlington), while last year Del. Wyatt B. Durrette Jr. and Del. John L. Melnick represented Northern Virginia in addition to Hobson. Durrette and Melnick both ran and unsuccessfully lost bids for statewide office. Since Hobson is from Alexandria and Almond from Arlington, Fairfax County, which has a separate judicial circuit and is Virginia's largest jurisdiction, is not represented at all.

The other committees that Northern Virginia has fewer than four members on are Finance; Roads and Internal Navigation; Education; Health, Welfare and Institutions; Commerce and Labor; General laws; Conservation and Natural Resources; and Corporations, Insurance and Banking.

All of these committees deal with issues that are important to the populous Northern Virginia area. Of the three major committees on which delegates feel they are adequately represented, only two -- Counties, Cities and Towns, and Privileges and Elections --deal with questions significant to the area.

There are seven smaller standing committees. Of these, Northern Virginia has no representatives on the Rules Committee, to which four legislators were newly appointed. However, of the six new appointments to the minor Militia and Police Committee, four are Northern Virginians.

Assignments are made on the basis of seniority party and geography, although political philosophy is widely viewed by delegates as playing a role in the selection process.

For example, the two new appointees to the Labor and Commerce Committee, which would consider legislation to allow collective bargaining by state employees if such a bill were proposed, are Dels. Bonnie Paul (RHarrison burg) and Eva Scott (IDinwiddie). Both are adamantly opposed to collective bargaining. One of them replaces former Del. Ira M. Lechner (D-Arlington), a well-known supporter of labor.

On the other hand, there were seven vacancies on the Privileges and Elections Committee, which will be voting on the Equal Rights Amendment. Of the 13 other members, only three favored the amendment, so the appointments were eagerly anticipated by ERA supporters, who lobbied to get on the committee. Of the seven new members, four favor the ERA, which gives them at least a slim chance of keeping it alive.

Nine of the 13 major committees have new chairmen, who are selected on the basis of seniority.

Del. Richard M. Bagley (D-Hampton) is the new chairman of the powerful Appropriations Committee, replacing Edward E. Lane, who resigned for an unsuccessful run for attorney general. Bagley, 50 is the president of an investment company and has been in the House since 1966.

Generally regarded as an affable, moderate legislator, Bagley is expected to have a difficult task running the Appropriations Committee. While Lane had a long personal friendship with former Gov. Mills E. Godwin, Bagley and the new governor Republican John N. Dalton, will be starting fresh. Bagley's impact could be influenced sharply by several experienced, aggresseive conservative legislators on the committee. With the exception of McDiarmid, the moderates on the committee are new.