Soldier (Danaus eresimus) in Bandera Co., looks about half-way between Monarch and Queen, but much rarer here

Queen (Danaus gilippus)

Monarch (Danaus plexippus)

Monarch (ventral) (Danaus plexippus)

Monarch (dorsal) (Danaus plexippus)

Monarch (right) & Queen (left)
(Danaus plexippus (L) & Danaus gilippus (R))
they become distasteful as larvae from their Milkweed foodplant

The Viceroy (Limenitis archippus) mimics the distasteful Milkweed eaters above, and gains protection by looking similar to them.
(They may be distasteful in their own right too)