The development of a fugue
Is the second section of a fugue.
It is comprised of episodes and entries. episodes contain fragments of the subject and sequences. Thus, it is not tonally stable.
Episodes are used to lead smoothly from one entry of the subject to the next.
Entries are in a closely related key, thus, tonally stable.
They contain one or more complete subjects...these multiple subjects can be linked. Devises found in an entry are: augmentation, diminution, melodic inversion, stretto and mixed modes.