diff --git a/telemetry/code/monitor/graph_plotter_rewrite.py b/telemetry/code/monitor/graph_plotter_rewrite.py
index 090db40..662178a 100755
--- a/telemetry/code/monitor/graph_plotter_rewrite.py
+++ b/telemetry/code/monitor/graph_plotter_rewrite.py
@@ -26,7 +26,7 @@ class Series:
     def addpoint(self, point):
         self.data.append(point)
         if len(self.data) > self.points:
-            del self.points[-1]
+            del self.data[0]
 
 class Plot(pyglet.window.Window):
     def __init__(self, series):
--
libgit2 0.21.2