Draco is the name of an astronomical constellation, of which Thuban is the alpha star. This constellation is the home of the Draconian Empire. Its reptilian inhabitants are often referred to as the Reptilians (or 'Lizzies'), the 'Reptoids' and 'Dinoids.' (But, please, note that the Vegan System, too, is the home of a "Lizard"-like humanoid civilization).
The Draconians are said to be master geneticists, who have been in the Universe for billions of years, and who have created several races. Because of this, they have come to consider themselves as some kind of gods and have grown an attitude of absolute superiority towards other races.
They are master 'controllers,' extremely mental in nature, and characterized by their lack of respect for free will.
Nowadays, Draco Reptilians can be found in nearly all known constellations in this part of the Galaxy. They have conquered major parts of the Orion Constellation, probably trying to gain control over the 'Orion Gateway.' Their main basis in the Orion Constellation is located in the Bellatrix system.

Physical appearance:

When we speak about the reptilian races in general, there are several variations, including insectoids, reptoids, dinoids (or saurians, as some people prefer to call them), as well as cross-breeds between them.

The most common species are:

See also Reptilian phenotype for more information.

When it comes to the Draconians in particular, Alex Collier claims there are two main castes: a caste of warriors that are in the 7-8 foot range, and who are apparently feared throughout the galaxy for their fighting abilities. There also is a royal caste, called the Ciakars. "They range from 14 to 22 feet tall and can weigh up to 1,800 pounds. They do have winged appendages and they are awesome beings. They're extremely clairvoyant and extremely clever, and they can also be extremely sinister."