diff --git a/AutoTx/AutoTx.cs b/AutoTx/AutoTx.cs
index a33465649b810566cdc8901ae247d9391322951c..dcebe5324d0095661a35bbd51fe0743363cb9e58 100644
--- a/AutoTx/AutoTx.cs
+++ b/AutoTx/AutoTx.cs
@@ -949,6 +949,7 @@ namespace AutoTx
         /// <summary>
         /// Assemble a dictionary with information about expired directories.
         /// </summary>
+        /// <param name="thresh">The number of days used as expiration threshold.</param>
         /// <returns>A dictionary having usernames as keys (of those users that actually do have
         /// expired directories), where the values are lists of tuples with the DirInfo objects,
         /// size and age (in days) of the expired directories.</returns>