Analysis of mitochondrial DNA (cytochrome c oxidase subunit I) barcode sequences revealed a deep genetic divergence (mean uncorrected p-distance = 3.5%) in populations of Codatractus melon (Godman & Salvin) from the northern and southern limits of its distribution in North America (Sonora, Mexico and Costa Rica) suggesting that the taxon is actually comprised of two closely related cryptic species. Male genitalia of C. melon from Sonora were morphologically similar to those from Jalisco, Mexico, and distinct from those of the closely-related C. arizonensis (Skinner) and C. sallyae Warren. Although the description of a new species of the C. melon group would appear warranted, we discuss taxonomic impediments that prohibit us from doing so at this time. We also provide information on the distribution and ecology of the northern population of C. melon. Preliminary barcode evidence is also reviewed which suggests that C. arizonensis may be comprised of more than one species.