diff --git a/lib/api/metric.js b/lib/api/metric.js
index 905dacf..cfc0dab 100644
--- a/lib/api/metric.js
+++ b/lib/api/metric.js
@@ -35,7 +35,7 @@ var client = require("../client");
  */
 function send(metric, points, extra, callback){
     if(arguments.length < 4 && typeof arguments[2] === "function"){
-        callback = tags;
+        callback = extra;
         extra = {};
     }