I was asked this question many times, so I think it should be present in a kind of FAQ in the future. Meanwhile...
Q: Where does the Instrumentation name come from ?
We here refer to the name that appears on the Instrumentation list in DevTools -> Instrumentation as showed in this screenshot.
By default we see android.test.InstrumentationTestRunner for all of our tests, so it would be very difficult to identify them
A: From the attributes of android.test.InstrumentationTestRunner in AndroidManifest.xml
That is, if the Label is not set in the manifest the default name is used. To set something meaningful for your tests set the label. In this case we shot Eclipse Android ADT manifest editor screen.