Location of rDNA genes and Ag-NOR sites on female and male mitotic chromosomes of L. cluvia (a–b) and L. sericata (c–d, e–f) using FISH with 18S rDNA probes (red signals, arrowheads) and silver impregnation technique. Chromosomes were counterstained with DAPI (blue). X, Y = sex chromosomes. Arrowheads indicate hybridization signals (a–d) and Ag-NOR sites (e–f) in both sex chromosomes. Bar = 10 μm.