DNA sequence data for a 3'UTR plus a patial protein coding sequence of the gene optix for multiple individuals for multiple races of Heliconius erato. The data is derived from direct sequencing, inferring polymorphisms from double peaks in the chromatograms. Haplotypes were determined by analytically phasing the data across all sequences using the program PHASE. Inferred sequence before phasing can be obtained in Genbank. A neighbor-joining tree inferred using PAUP* is attached as a treeblock.