HANOVER, N.H., May 13--Paced by hard-hitting midfielder Pete Sieglaff, the varsity lacrosse team plowed through a hot, humid afternoon to overcome Dartmouth 10 to 8 today.

Injuries to Gil Leaf, Dave Bohn, and Gil Bamford combined with excessive heat to put the Crimson at less than full strength, but Dartmouth could muster little more than spirit and a top-flight defenseman named Pete Sly. Sly showed great improvement over last year, containing injured Crimson playmaker Grady Watts to one goal and one assist.

Two minutes after the Indians picked up the opening face-off, Sly demonstrated his offensive prowess to an admiring Crimson team in running the ball 70 yards before passing to the Dartmouth creaseman for the first tally of the day.

Sieglaff countered less than two minutes later, grabbing a loose ball in front of the Indian crease and whipping it past the dumbfounded goalie.

"They Got Nothin'"

Three minutes later, as the teams broke from their huddles after a Dartmouth time-out, an Indian yelled "They got nothin'! They got nothin'!" Within ten seconds Watts had brought the ball in from offside, spun off his defenseman, Sly, and stuffed the ball into the nets to put the Crimson ahead 2 to 1. Sixty seconds later Sly watched Dave Nyhan convert a Watts pass into the third Harvard tally.

With the score 4 to 2 at the start of the second period, Woody Spruance scored on the backhand scoop shot he has perfected this year, and Harvard and Dartmouth twice traded goals to push the score to 6-4 at the end of the half.

An uneventful third period featured hard defensive play and a single Dartmouth goal at 9:28. Dave Grannis and Arnie Margoluis consistently frustrated the Green attack, and Henry Field effectively handled Crimson clearing activity with Grannis.

Sieglaff opened the fourth period with a quick score at 0.13. John Reese followed a minute and a half later, pivoting between two defensemen and drilling the ball into the cage.

With time getting short, repeated wild passing by the Indians showed signs of Dartmouth panic. But at 5:50 an Indian shot nipped the nets, making it 8 to 6. Midfielder Joe Prahl and a Dartmouth attackman traded tallies in ten seconds to boost the score to 9 to 7 with less than five minutes remaining.

Sieglaff closed the Harvard scoring at 12:30 with his third goal of the afternoon, followed two minutes later by the final Indian tally. One little, two little, ten little Indians.

The varsity will meet a squad from Middleburg Wednesday in what is regarded as a tune-up for Saturday's game with Yale.