Pretreatment of embryos of a nondiapause strain of the migratory grasshopper (Melanoplus sanguinipes) with actinomycin D, followed by posttreatment of chromosome preparations obtained from them with NaOH and Sörenson's buffer, induced longitudinal differentiation of each chromosome after Giemsa staining. We consider such crossbands to be G-bands because of the following: (i) they were present along the entire length of each chromosome; (ii) the centromeric region of each chromosome was unstained; (iii) each pair of chromosomes showed its own distinctive banding pattern; (iv) the banding pattern was consistent from cell to cell for the same pair of chromosomes; and (v) a similar procedure is known to induce G-bands in human chromosomes. C-bands induced by the Ba(OH)2 technique showed constitutive heterochromatin to be confined to the centromeric region of each chromosome.Key words: Melanoplus, G-bands.
