We report here a cytogenetic analysis of the melon fly, Bactrocera Cucurbitae, Coquillett (Diptera: Tephritidae), a species of significant agricultural importance. The mitotic karyotype and detailed photographic maps of the larval salivary gland polytene chromosomes of the species are presented. The mitotic karyotype consists of six pairs of chromosomes including one pair of heteromorphic sex (XX/XY) chromosomes. The heterogametic sex is ascribed to the male. The analysis of polytene chromosomes has shown a total number of five long polytene elements (10 polytene arms) that correspond to the five autosomes. The characteristic features and the most prominent landmarks of each polytene chromosome are presented. The proposed chromosomal homology between B. Cucurbitae and Mediterranean fruit fly, Ceratitis capitata (Wiedemann), was determined by comparing chromosome banding patterns. The detection of heterozygous chromosome inversions in two strains is shown and discussed. The current study provides workable polytene chromosome maps of the species and compares our results with previous reports. We show that these maps can be used for cytogenetic studies in the species and for comparative studies among the tephritid species. They also can support the development of control methods and clarify the taxonomic status of B. cucurbitae.