wpmem_login_form_before

/**
 * This example will add the HTML before all "short forms"
 */
add_filter( 'wpmem_login_form_before', function( $html ) {
    return '<p>Some message here</p>';
});


/**
 * Specify the action to limit the message to before a
 * specific "short form" form.  
 *
 * The possible action switches are:
 *   - login
 *   - pwdreset
 *   - pwdchange
 *   - getusername
 *
 * The following example would add a message before 
 * the login form only:
 */
add_filter( 'wpmem_login_form_before', function( $html, $action ) {
    if ( 'login' == $action ) {
        return '<p>Some message here</p>';
    }
}, 10, 2 );