The fugue begins with the theme in the tenor line from measures 1-4. The alto takes over from meausre 5-8 while the tenor plays some cute accompaniment. Soprano line comes in at measture 9 and has the theme until 12. 13-16 is the bass entrance and thematic moment.
Now that all four parts are in, Bach lets us soak up the four part texture for 3 measures before bring the theme back in the tenor line from measures 20-23. When then have 8 measures of four part texture before bringing the theme back in the sopranos measures 32-35. Basses m. 36-39. This time there are 5.5 measures of four part texture before the middle voices (alto/tenor) bring back the theme in measures 45-48. 57-59 the soprano and alto has it, while 59-62 is the bass/tenor moment.
For the entire last page Bach just plays around the rhythms of the theme and throws those in, but never fully gives us the theme for the rest of the fugue.