Answer
The bulb will glow more brightly when it is in series with the ammeter.
Work Step by Step
A voltmeter has a much, much higher resistance than an ammeter, so the circuit’s resistance is lower when the bulb is in series with the ammeter. By Ohm's Law ($I=\frac{\epsilon}{R}$), the battery supplies more current in that case, and the bulb glows more brightly.
