Are you using a battery powered light that you'll charge from the USB, or a dedicated light that will run directly from the hub? If the latter then do as @hippy says, run them both in parallel (ie both the positives leads go together onto the hub, and both the negative leads together). You want the igaro to receive the full well from the hub when the light is off, which you cannot do if they're wired in series.
Are you using a battery powered light that you'll charge from the USB, or a dedicated light that will run directly from the hub? If the latter then do as @hippy says, run them both in parallel (ie both the positives leads go together onto the hub, and both the negative leads together). You want the igaro to receive the full well from the hub when the light is off, which you cannot do if they're wired in series.