One solution to your problem probably is Reverse Tether:
Other than your hotspot functionality (which lets you use your phones Internet connection with other devices via Wifi), this allows you to use your computers network via USB, as the screenshots imply. Thus your phone gets a (configurable) IP address (pic1: "Desired IP") matching your computers (pic1: "Gateway IP"; it is important that both are part of the same subnet), and then you can access your computers web services from your Android device as described before (using the computer's IP).
Drawback: This solution requires your device to be rooted. I will check further, maybe I find a similar solution not requiring root, and then will update my answer with that new information.
If your computer is equipped with Wifi, an "adhoc connection" could also provide a solution. You might want to take a look at the question How to connect android wifi to adhoc wifi? for details on this. And there is a brand new article just published today at PC Advisor: Connect Android phone to Ad Hoc network, which might be even more helpful to you.