The Mesopotamian Blue Family is the family of Varjak.
The Mesopotamian Blues, who are Varjak's family, are the first cats to be introduced in Varjak Paw. They are, in order of age: The Elder Paw, Father Paw, Mother Paw, Juni, Jasmine, Julius, Jay, Jethro, Jerome and Varjak. For some reason all the young cats except for Varjak have names starting with the letter J.
All of them, except Varjak and the Elder Paw, are extremely aloof and look down on other cats, considering themselves the noblest of cats. Julius often bullies Varjak because he has amber eyes.
Until around the middle of the book, the Mesopotamian Blues have lived for generations in the Contessa's house, where Jalal first settled. When the Gentleman comes with his two black cats, a body is removed from the house, which is actually the Contessa's. The family refuse to believe this, and stay in the house where the Gentleman is feeding them caviar. After Varjak Paw saves them from the Gentleman, the family still refuse to move, but this time because of old habit. Varjak leaves them to start his life in the city.
They are not heard from in The Outlaw Varjak Paw, despite them saying that Varjak could return any time.