This chapter takes a metapoetic approach to Lucretian allusion to show that the DRN figures the phenomenon of echo as a metaphor for literary appropriation. Lucretius culminates his discussion of acoustic phenomena and hearing with the example of the echo (DRN 4.549–94). Insofar as echo is introduced as the most prominent effect in the perceptible world of the atomic reverberations that give rise to auditory aisthēsis, I argue that Lucretius' multiple allusions to earlier poetry in this passage also serve to illustrate metapoetically the process itself of hearing. The ideas inherent in this Lucretian passage find parallels in the fragmentary papyri of Philodemus.