The rice black bugs (RBB) in the Philippines is a complex of cryptic species. One of the major characters used in understanding differentiation in this pest is the shape of the closed first marginal cell of the left and right wings. Since this character is used as one of the taxonomic character in the characterization of the different species, consistency (symmetry) in the shapes of the character should be investigated to shed light into its nature. Geometric morphometrics was used as a tool in this study to analyze sources of variation within and between populations of the pest. A total of four landmarks were used to approximate the shapes of the first closed marginal cell where the extent of intra- and inter-population differences in the shape was determined via the method of Procrustes ANOVA. Significant inter-individual and between population variability were observed. It is important to note in this study that the existence of morphological differentiation within each population may indicate underlying genetic variability and which might explain the resilience of the organism to various pest management approaches.