Populations of Drosophila melanogaster from Eugene and Medford, Oregon, and from Napa and Bakersfield, California, were studied to determine whether second chromosome allozyme allele (aGpdh, Mdh and Adh) and inversion [In(2L)t and In(2RJNS] frequencies exhibit dines, as do populations along the East Coast of the United States. Analyses of the aGpdh and Adh data show the West Coast data to have regression coefficients (regressing allele frequency on degrees north latitude) of the same sign and comparable magnitudes as East Coast populations; however, the regression coefficients are not statistically significant, perhaps because of the small number of localities sampled. Inversion frequencies show interpopulation differentiation, being highest in the southern most (Bakersfield) population, but no statistically significant clinal tendencies. Analyses of data from extracted second chromosomes from the two Oregon populations show that of the twelve intrapopulation comparisons between four allozyme loci (aGpdh, Mdh, Adh, and Hex C) only one (aGpdh vs Hex C in Medford) shows statistically significant linkage disequilibrium. Of the nine Eugene intra-1 Paper No. 4875 of the Journal Series of the North Carolina Agricultural Experiment Station,