rpenmanparker 

Calories is another way of saying watts-hours. Literally. If you put out watts for a time, you are burning calories. And we know your power output is rated to your heart rate. Cycling or running, if your heart rate is similar, so will be the calories you burn over the same amount of time. As WhyFi suggests, the notion that running burns more calories is predicated on the tendency of some folks to cycle very casually. At the same fitness level, any activities that stress the heart the same will cause the same number of calories to be burned. So it is not how far you run and cycle, it is how hard for how long.