The DNA sequence of the coding region of the wild-type and mutant alleles of the white eye gene from the melon fly, Bactrocera cucurbitae Coquillett, was obtained. The mutant white eye allele had a single base pair mutation at the 5′ end of intron 4b in the RNA splice recognition site. Due to the disrupted splice recognition site, intron 4b was not removed from the mutant RNA transcript. The resulting mRNA transcript was 68 bp longer than that of the wild type, containing a frameshift and premature stop codon. Transport of pigment precursors would be blocked, resulting in a lack of pigmentation deposition consistent with the known mutant phenotype.