diff --git a/src/Cypher/Statement.php b/src/Cypher/Statement.php
index f7e3490..5d756f8 100644
--- a/src/Cypher/Statement.php
+++ b/src/Cypher/Statement.php
@@ -39,7 +39,7 @@ class Statement implements StatementInterface
      * @param string|null $tag
      * @param StatementType
      */
-    private function __construct($text, array $parameters = array(), $tag = null, StatementType $statementType)
+    private function __construct($text, array $parameters = array(), $tag = null, StatementType $statementType = null)
     {
         $this->text = (string) $text;
         $this->parameters = $parameters;