This is better, it selects the transforms instead of the shapeNodes:
int $polyLimit = 300;//Change this number for threshhold
select -cl;
string $sel[] = ls -type "mesh"
;
string $polySel[];
clear $polySel;
//Loop through all polygon objects
for($i=0;$i<size($sel);$i++){
int $polyCount[] = `polyEvaluate -f $sel[$i]`;
if($polyCount[0] < $polyLimit){
string $transform[] = `listRelatives -p $sel[$i]`;
$polySel[size($polySel)] = $transform[0];
}
}
//Select objects
select -r $polySel;