As is mentioned in the entry FORMER, latter means "the second of two": "I prefer your latter suggestion to your first." Latter also has the meaning of "more advanced in time" and "near the end": "In the latter years of his life, he was a happy man." "In these latter months she has become angry and frustrated." In sentences such as these two, later, being the comparative degree of late, could be substituted for latter. However, later is more likely to be used to refer largely or solely to time references, whereas latter can refer not only to time but to any kind of series: "I may be free or occupied in the morning; in the latter event, I shall have to see you later in the day."
Dictionary of problem words and expressions. Harry Shaw. 1975.