Simply Maya User Community - View Single Post - " Select curves longer then "

This should do it. Change 10 to whatever length you want. Select your curves, then run the script in the MEL script editor.

Code:

string $curves[] = `ls -sl`;
float $length = 10;

select -cl;

for ($curve in $curves)
{
    float $curveLength = `arclen $curve`;

    if ($curveLength > $length)
        select -add $curve;
}