diff --git a/collects/2htdp/private/universe.ss b/collects/2htdp/private/universe.ss
index eaab74f268..8bd4ec0798 100644
--- a/collects/2htdp/private/universe.ss
+++ b/collects/2htdp/private/universe.ss
@@ -343,7 +343,7 @@
       (let ([make-bundle make-bundle])
         (lambda (state mails bads)
           (check-arg-list 'make-bundle mails mail? "mail" "second")
-          (check-arg-list 'make-bundle bads iworld? "mail" "third")
+          (check-arg-list 'make-bundle bads iworld? "iworld" "third")
           (make-bundle state mails bads))))
 
 ;; Symbol Any (Any -> Boolean) String String -> Void