diff --git a/src/Getopt.php b/src/Getopt.php
index 5ed12f6..aa1a644 100644
--- a/src/Getopt.php
+++ b/src/Getopt.php
@@ -637,7 +637,7 @@ public function setAliases($aliasMap)
     /**
      * Define help messages for options.
      *
-     * The parameter $help_map is an associative array
+     * The parameter $helpMap is an associative array
      * mapping option name (short or long) to the help string.
      *
      * @param  array $helpMap