Lix Tetrax is the demon of the wind, in the Testament of Solomon.
Lix is a Greek term relating to the earth, while Tetrax refers to a four-season year. The name has been identified with the Ephesian name connected to the wind found on a tablet from Crete. It is the Howling Whirlwind Demon born of the Great One — causes fever and burning, but if it feels kindly toward you, will refresh you with cool breezes and lead you to refuge.
I create divisions among men, I make whirlwinds, I start fires, I set fields on fire, and I make households non-functional. Usually, I carry on my activity in the summertime. If I get the chance, I slither in under the corners of houses during the night or day. I am the direct offspring of the Great One.' - The Testament of Solomon 7:5
It is not known who the Great One is. It is speculated to be a reference to Beelzeboul or even to the goddess Artemis, who was known as "The Great" and referenced by TSol in a later passage.
When asked in which constellation the demon resides, he replied:
Toward the very tip of the horn of the moon when it is found in the South - There is my star. Therefore, I was assigned to draw out the fever, which strikes for a day and a half. As a result, many men, when they see (this), pray about the day-and-a-half fever, (invoking) these three names, 'Baltala, Thallal, Melchal,' and I heal them. - The Testament of Solomon 7:6
Lix Tetrax is thwarted by the archangel Azael.