According to p. 95 of the MLA Handbook 8th ed. Spell out months in the body of your paper and abbreviate as follows in your works cited list:
January = Jan.
February = Feb.
March = Mar.
April = Apr.
May = May
June = June
July = July
August = Aug.
September = Sept.
October = Oct.
November = Nov.
December = Dec.
Example with an author:
Lustig, T. Gutenberg: First modern inkmaker? The inventor of movable type probably also created the first workable printing ink. Spiral, 2015.
If this article did not have an author it would be cited as:
Gutenberg: First Modern Inkmaker? The Inventor of Movable Type Probably Also Created the First Workable Printing Ink. Spiral, 2015.
Start with the name of the article, book, or web page if no author is given.
The Library of Congress. "American Notes: Travels in America, 1750-1920." American Memory, 3 Dec.
2013, http://memory.loc.gov/ammem/lhtnhtml/lhtnhome.html. Accessed 15 May 2016.
Author of the site: The Library of Congress.
Title of the Web page: "American Notes: Travels in America, 1750-1920."
Title and subtitle of the overall Web site: American Memory,
Date of electronic publication, of the latest update, or of posting: 3 Dec. 2015,
Web address, or URL, of the source: http://memory.loc.gov/ammem/lhtnhtml/lhtnhome.html.
Date when you accessed the web page: Accessed 15 May 2016.
[The above information is based on the MLA Handbook 8th edition and Purdue OWL]