Queen

(From 3.5e Monster Manual I - 2003):

Formians hail from the plane of Mechanus. They seek to colonize all that they see and incorporate all living things into their hive as workers. 

Expansionist in the extreme, formians are dedicated to spreading their colonies until they have taken over everything and their order is unquestioned. To further this end, they attack all other creatures, usually to put them to work building and expanding cities. Formians maintain these “conscripted” workers as well as those mentally dominated by the power of their taskmasters. 

A formian resembles a cross between an ant and a centaur. All formians are covered in a brownish-red carapace; size and appearance differs for each variety.

Formians build fabulous hive-cities in which hundreds of the creatures dwell. They are born into their station, with no ability to progress. Workers obey orders given by warriors, myrmarchs, or the queen. Warriors carry out the will of their myrmarch commanders or the queen. Myrmarchs take orders only from the queen herself, although they have different ranks depending on services rendered. These are not positions of power but of prestige. The most prestigious of the myrmarchs guard the queen. Taskmasters are equal in rank to warriors but seldom interact with other formians.

The Queen: The formian queen sits at the center of the hive-city, her bloated form never moving from the royal chamber. She is served and guarded by the most loyal myrmarchs. 

The formian queen cannot move. With her telepathic abilities, though, she can send instructions to and get reports from any formian within her range.

The queen speaks Formian and Common, although she can communicate with any creature telepathically

Combat: The queen does not fight. She has no ability to move. If necessary, a team of workers and myrmarchs (or dominated slaves) haul her enormous bulk to where she needs to go. This sort of occurrence is very rare, however, and most of the time the queen remains within her well-defended chambers. 

Despite her utter lack of physical activity, the queen can cast spells and use spell-like abilities to great effect in her own defense as well as the defense of the hive-city. 

Spells: The queen casts arcane spells as a 17th-level sorcerer. 

Typical Sorcerer Spells Known (6/8/7/7/7/7/6/6/4, base save DC 15 + spell level): 0—acid splash, arcane mark, daze, detect magic, light, mage hand, read magic, resistance, touch of fatigue; 1st—comprehend languages, identify, mage armor, magic missile, shield; 2nd— hypnotic pattern, invisibility, protection from arrows, resist energy, scorching ray; 3rd—dispel magic, heroism, nondetection, slow; 4th— confusion, detect scrying, Evard’s black tentacles, scrying; 5th—cone of cold, dismissal, teleport, wall of force; 6th—analyze dweomer, geas/quest, repulsion; 7th—summon monster VII, vision, waves of exhaustion; 8th—prismatic wall, temporal stasis. 

Spell-Like Abilities: At will—calm emotions (DC 17), charm monster (DC 19), clairaudience/clairvoyance, detect chaos, detect thoughts, dictum (DC 22), divination, hold monster (DC 20), magic circle against chaos, order’s wrath (DC 19), shield of law (DC 23), true seeing. Caster level 17th. The save DCs are Charisma-based. 

Telepathy (Su): The queen can communicate telepathically with any intelligent creature within 50 miles whose presence she is aware of.

(From Planescape: Planes of Law Monstrous Supplement - 1995):

"Had mine eyes ever beheld such beauty? To think, all fashioned by a bug!"

- Unknown traveler upon reaching a formian city

Native to Arcadia, formians are also called centaur ants. As their moniker indicates, they appear to he uprightwalking ants, but their sentience is that of warmblooded creatures as opposed to insects. They’ve always inhabited Arcadia, and sages say they always will. Though formians found on the Prime make war on each other, Arcadian formians of different hives have learned to live together peaceably. 

Similar to true ants, there are three basic types of formians: the worker, the wamor, and the myrmarch. (A fourth type, the queen, is extremely rare.) Unlike ants, formians’ waists are flexible; thus, they often move with only four legs, their heads and thoraces raised. Their forelegs are jointed at the wrist and have three opposing claws, which they can use to manipulate objects and to attack. Formians come in various subdued colors, which serve no function other than to indicate their cities of  origin.

Formians of warrior level and higher can communicate with humans, though their version of common sounds more like eerie chittering. They communicate with one another in their own speech, which is incomprehensible to most other beings.

The Queen: The aueen is half again as large as a mvrmarch. She is in charge of administering the city and never leaves the central hive, and therefore her legs have atrophied.

Combat: Myrmarches attack with their mandibles and a poisoned sting. The poison causes 3d12 points of damage and paralyzes opponents for 1d4 turns (save versus poison to take half damage and avoid paralyzation).