N.Y. Lien Law § 63

§ 63. Service of answer on state or public corporation. In an action\nto foreclose a lien for a public improvement each defendant named in the\noriginal summons shall within forty days after the service of the\ncomplaint on him serve upon the state or public corporation, a copy of\nhis answer When the city of New York is a party such service shall be\nmade on the corporation counsel.\n