Edna St. Vincent Millay’s poem beginning “What lips my lips have kissed” is a Petrarchan sonnet, a kind of poem associated from the very beginning with heterosexual love and thus a kind of poem that seems appropriate to the focus of Millay’s work.

The first eight lines of a Petrarchan sonnet are called the “octave” and rhyme as follows: a/b/b/a a/b/b/a.  Millay’s poem follows this rhyme scheme exactly.  The last six lines of a Petrarchan sonnet are called the “sestet” and may rhyme in a variety of possible ways.  Millay chooses the following rhyme scheme for her sestet: c/d/e/d/c/e. Petrarchan sonnets are more difficult to write in English than in the original Italian, since there are fewer rhyming words in English than in Italian, in which many words end with vowel sounds.

Petrarchan sonnets often involve some significant change in argument or meaning (as well as form) between the octave and the sestet.  This kind of change occurs in Millay’s poem, where the language of the sestet is more metaphorical than the language of the octave. The octave makes clear the speaker’s actual sexual relations with various “unremembered lads” (7). The octave therefore mentions such precise physical details as “lips,” “kissed” (1), “arms,” “lain” (2), “head” (3), and

. . . lads that not again

Will turn to me at midnight with a cry. (7-8)

In contrast, in the sestet the speaker simply compares herself to “a lonely tree” (9) and compares her various lovers to vanished “birds” (10). The sestet is much less overtly erotic than the octave. The sestet thus functions as a kind of metaphorical comment on the precise, sexually detailed octave.

This kind of separation between octave and sestet seems appropriate to the meaning of the poem, partly because the octave deals with the past and the sestet deals with the present.  The octave deals with past experiences; the sestet deals with present memories of those experiences. In this case, then, the form of the poem is also functional: it helps subtly reinforce the work’s overtly stated meanings.

Interestingly enough, Petrarch’s own sequence of sonnets, the Rime Sparse or Canzoniere, also deal with memories of love, but the love described in Petrarch’s poems is never overtly sexual (much as the speaker might wish it were). Petrarch’s sequence of poems celebrate a virtuous virgin, Laura, who seems far removed, at least in her sexual conduct, from the kind of speaker presented in Millay’s sonnet.