What is the symbolism behind removing the bishop's mitre during Mass?

[Oumashta]

I’m an altarserver and sometimes I notice that there are certain times when we must hold the bishop’s mitre and crozier and give him back his skull cap, and there are certain times during Mass when we must remove it again. Is there any symbolic meaning of this? I still find it quite confusing and somewhat complicated to remember when to remove it and when to give it back to him, but thankfully other altarservers remember I’m sure there is some sort of symbolic meaning behind this, right? (As with most other liturgical actions during the Mass)

Could anyone help me understand this?

Thanks and God bless!

 

[Vico]

The bishop removes his mitre (a symbol of authority) or zucchetto out of respect:

• to venerate the altar,
• before the Gospel,
• for the profession of faith,
• for the Offertory,
• after the Prayer over the Offerings.

 

[Gorgias]

There are two things going on here. The bishop will remove his mitre when he prays to God. He will also remove his zuccheto between the Prayer over the Offerings and the end of the Communion Rite, in reverence to the Real Presence.