We report the genomic sequence of hscp, a sodium channel alpha subunit gene for Heliothis virescens. A 32-kb genomic clone and six independent RT-PCR products covering almost the entire coding region of the gene, contained thirty-one deduced exons with a translation of 1695 residues. Overall amino acid similarity to the para locus of Drosophila melanogaster was 86%. The transcription of the gene was complex. Alternate splicing was evident for five optional exons and a pair of mutually exclusive exons. A number of alternatively spliced mRNA revealed a deduced translation product that included only the first homology domain. We also report the first partial sequence for hDSC1, a presumed orthologous of the DSC1 sodium channel alpha subunit gene of D. melanogaster.