Hi, I've been workin on this fugue, trying to apply my new knowledge.
It's in G major, and there's controversy. In the subject the dominant note (D) appears quite clearly in measure 3. Is it supposed to be transposed tonally, i.e. a fourth up (G) instead of a fifth (A)? I didn't. As you can see in bar 8 it is as an A.
It really is an ambiguous case "by the book". Since the D appears prominently but already in the third bar. So I tried to make the answer as you can see, and as it sounded good it stayed that way.
The structure is:
Exposition, where the 4 voices enter and the countersubject is written in invertible counterpoint.
Divertimento, sequence or episode (measure 22) that modulates to the dominant (D).
Counter-exposition (measure 26), using inverted subject and countersubject.
Divertimento (m. 36) using Corelli's Leapfrog with the subject motive with other schemata and Cudworth cadence (which I like to use a lot).
Stretti (m. 44) and mini-exposition with pedal note.
Divertimento (m.58) in the subdominant area with plagal cadence and new Cudworth to return to the tonic.
Coda (m 65) with perfect authentic cadence.
As always happens to me, I'm sure I've missed parallels all over the place. But hey, someday I'll get closer....