Summary: Act V: Scene v
The scene is now Volpone's house. Mosca and Volpone enter; Mosca is dressed as a clarissimo, or great nobleman, and Volpone wears a commandadore's (sergeant's) uniform. They briefly discuss Volpone's plan to blatantly mock those he has duped. He leaves, and Mosca makes some cryptic comments to the effect that Volpone won't be regaining his own identity before he comes to terms with Mosca. He gives Nano, Castrone and Androgyno some money before telling them to find new work. Mosca again cryptically comments that he will either "gain" by Volpone, or "bury him" (V.v.14).
Summary: Act V: Scene vi
The scene has now moved to a street, where Corvino and Corbaccio are disguised. Volpone enters in disguise. He begins asking the two what they have inherited from the dead magnifico, Volpone; they react to his questions with predictable annoyance. Volpone annoys them further by reminding them of what they did in their failed attempts to gain Volpone's inheritance; how Corbaccio signed his own son out of his will, and how Corvino prostituted his wife. They leave, and Volpone goes on to his next victim.
Summary: Act V: Scene vii
Voltore enters, walking down the street, completely disbelieving that he has lost the inheritance to Mosca, a parasite. Volpone comes up to him, and begins asking about one of his own properties, a small "bawdy-house" (V.vii.12) (equivalent to a seedy night-club or whorehouse). He implies that since Voltore is the old magnifico's heir, he is the one to talk to about purchasing this property and perhaps renovating it; it is, after all, nothing at all to someone of Voltore's newfound wealth and stature. Volpone's irony drives Voltore to frustration, and he leaves. Volpone returns to Corbaccio and Corvino.
Summary: Act V: Scene viii
Corbaccio and Corvino enter, and watch Mosca pass by in his fine robes. They are infuriated, and even more so when Volpone arrives to continue taunting them. He now inquires whether the rumours about the parasite are true; knowing that they are, he proceeds to admonish Corbaccio and Corvino for having so handily been defeated by Mosca, and having lost their dignity in the process. Corvino then challenges Volpone to a fight, but Volpone wisely backs off.
Summary: Act V: Scene ix
Voltore makes a cryptic threat to Mosca: though he is in summer now, his "winter shall come on" (V.ix.1). Mosca tells Voltore not to speak foolishly. Volpone then arrives, and hoping to taunt Voltore further, asks him if he wants Volpone to beat Mosca, to avenge the terrible disgrace Voltore now suffers for being gulled by a parasite. Further adding insult to injury, he demands to know whether or not Mosca's inheritance is in fact a joke. After all, Volpone implies, a lawyer couldn't have been outsmarted by a parasite. Voltore leaves, tormented and humiliated.
Analysis: Act V: Scenes v-ix
The issue of social class had been treated indirectly in the play through the character of Mosca, forced to be Volpone's parasite due to his poverty; but Jonson deals with it explicitly here. The Elizabethans had a fairly rigid conception of social class, certainly by today's standards. Volpone remarks it is a pity that Mosca was not a born a clarissimo, because he plays the part so well; Mosca replies aside that he may very well keep his "made one" (V.v.4), turning Volpone's comment into a piece of dramatic irony. Mosca puns on the word "made", hoping to be a self-"made" man, and achieving it through "manufacture" and "fabrication", two other senses of the word "made". This implies that Mosca's social status is now fake, artificial. So Volpone's lies have resulted in the destabilization of the social order. This destablization is reinforced by the anger Voltore express about being dispossessed by "a parasite! A slave!" (V.vii.1), talking to himself as he walks along the street, seemingly obsessed by it, almost driven to insanity. It is symbolized by Volpone's own decision to effectively trade in his identity as a nobleman for one as a commandadore, all for the sake of the pleasure of taunting someone for having failed to inherit an estate-ironic (situationally), because he loses that very same estate in the process.
In the Elizabethan world-view, the social order embodied in the class system is fundamentally linked to the order of the universe, making any destablization in the class system profoundly disturbing and in need of rectification. But the attitude of the play towards class more complex and potentially contradictory; after all, the people mainly upset by Mosca's inheritance are the legacy hunters, who are morally dubious; and Mosca behaves no differently than any of the characters of a higher class level than him. In short, it is difficult to determine whether Jonson endorses the Elizabethan idea of class, or actually criticizes it. Further indications will be given in the play's final scenes; an essay written on this question would be a challenging but interesting one.
Read more about Mosca and his duplicity.