Despite instant analyses after the Nov. 2 midterm elections that indicated moderate Republican survivors would become more resistant than ever to Reaganomics in the new Congress, the group appears to be split.

Republicans who had struggled hardest for moderation were most affected in the elections by President Reagan's policies.

In the House, 16 of 26 GOP incumbents who lost were from Frost Belt districts where the recession is most intense. The "Gypsy Moths," moderate northeastern and midwestern Republicans who came together to soften cuts in social spending and to moderate military growth, saw their ranks thinned by one-fourth.

In the Senate, all incumbent Republicans who had close calls were from the party's moderate wing. While conservatives such as Orrin G. Hatch (Utah) and Malcolm Wallop (Wyo.) won comfortably, such moderates as John H. Chafee (R.I.), David F. Durenberger (Minn.) and John C. Danforth (Mo.) barely avoided electoral oblivion. Chafee and Danforth won with only 51 percent of the vote, Durenberger with 53 percent.

In addition, Millicent Fenwick and David F. Emery, moderate Republican House members who had been heavy favorites to win Senate seats, were defeated in New Jersey and Maine, respectively.

Indicative of the apparent split, one leader of the Gypsy Moths said he intends to pursue more parochial regional interests, even as another contended that the group represents potentially a key bloc of votes in an alliance with Democrats. A third Moth predicted only stronger pressure to reduce defense spending.

The moderates do not have to take the lead in breaking with President Reagan and his exceptional degree of party control in the current Congress. The GOP leadership of the House and Senate, which is to the right of the party's moderate wing, is splitting with him.

In the Senate, the election results are likely to strengthen the hands of leaders who had already begun to dissent from Reaganomics, including Majority Leader Howard H. Baker Jr. (Tenn.), Finance Committee Chairman Robert J. Dole (Kan.) and Budget Committee Chairman Pete V. Domenici (N.M.).

They have helped force the president to reverse himself and support a deficit-reducing tax increase earlier this year to offset the cut he pushed through Congress in 1981. They have also told him that there can be no further tax cuts and that he must moderate his proposed defense buildup rather than make domestic spending programs bear the full burden of deficit reduction.

This Baker-Dole-Domenici leadership is in position to define the Senate's legislative agenda more or less independently of the president.

For moderate House Republicans, who have far less leverage than their Senate counterparts, the situation is much more complex.

The Gypsy Moths were never quite able to coalesce. They were whipsawed throughout the current Congress by conflicting loyalties to the administration and their beleaguered districts.

Their objectives were defensive, to keep the administration's budget cuts from scraping too deeply into health, education and welfare programs of importance to their districts stretching from New England to Minnesota.

But the Moths could never quite decide whether what they really wanted was to modify the administration program -- to "give Reaganomics a human face" -- or to distance themselves politically from Reagan.

The Moths never learned to play budget hardball with the skill and toughness of other key groups in the Reagan majority coalition, including conservative Democrats and far-right Republicans, known as the "Boll Weevils" and the "Yellow Jackets," respectively.

Then the voters determined that, of the 25 to 30 Republicans who had some part in the Moths' organization, seven will not return next January. Six were defeated by Democrats who turned Reaganomics into a liability. The seventh was Fenwick.

"I feel like I was mugged," said Rep. Lawrence J. DeNardis (Conn.), still bewildered after his defeat. "What profound statement do I have about it all? I don't. I'm still licking my wounds."

In the election's aftermath, there are signs that instead of becoming more assertive, the organization may split further.

Cochairman Carl D. Pursell (Mich.) said he is thinking of concentrating on issues of more direct concern to his state and region, rather than broader questions involving the Northeast-Midwest area.

"I'm shifting my priorities to some extent,"he said. "I'd like to refocus some of it right to the Midwest." He noted that in the GypsyMoths "the dominant elements were from the New England states" while the Midwest was "very weak."

Pursell said he is considering creation of separate regional groups which, when they have a common position on an issue, could join forces.

Pursell and cochairman Bill Green (N.Y.) attempted to downgrade losses among the Moths, contending that five of the seven defeated members--Fenwick, Margaret M. Heckler (Mass.), Jim Dunn (Mich.), Charles F. Dougherty (Pa.) and Arlen Erdahl (Minn.) -- were not very active in the group.

Green contended that the election is likely to give new impetus to the drive to reduce growth in military spending.

Another Gypsy Moth, Rep. Jim Leach (Iowa), found two reasons to be optimistic about the role of his wing of the GOP. "Despite the fact that a number of moderate Republicans lost, the mandate was for moderation," he said.

In addition, Leach argued that moderate House Republicans have the potential to assume in the new Congress a role parallel to that played by the conservative southern Democrats in the current Congress.

"The most important conjecture for the new House is the locus of decision-making," he said, noting that in 1981 and during most of this year, the balance of power often fell with Boll Weevils, who had the votes to make or break administration proposals.

Next year, Gypsy Moth votes could become critical, Leach noted, particularly on attempts to override vetoes. This view is privately shared by some in the House Republican leadership.

DeNardis said he thinks that a major reason for the outcome in his New Haven-based district was his failure to emphasize his role in the Gypsy Moth group seeking to change Reaganomics.

"My campaign did not convey the clear message that I was part of a group that was trying to correct the harsher aspects of the Reagan economic program," he said.

The result was that his opponent, Bruce A. Morrison, who won by 1,464 votes, was able to conduct a negative campaign "inferring that DeNardis and the Republicans were going to cut the hell out of Social Security," DeNardis said.

With the taste of failure still bitter, DeNardis said, however, "I don't blame Reagan. I blame myself, and I blame my campaign organization."

In addition to DeNardis and other defeated Moths already mentioned, Rep. Harold C. Hollenbeck (N.J.) lost to Robert C. Torricelli.