Ilyocoris cimicoides and Notonecta glauca (ovarioles): Schiff-Giemsa (24, 25, 28) and FISH with 18S rDNA (26, 27) 24–27 Ilyocoris cimicoides: 24 interphase trophocytes with 2 and 4 heteropycnotic elements, and a metaphase tetraploid trophocyte 25 interphase trophocytes with 16 and about 32 heteropycnotic elements 26 18S rDNA signals on the sex chromosomes in a oogonial diploid metaphase plate 27 a, b 18S rDNA signals on the heteropycnotic elements in interphase octoploid trophocytes 28 Notonecta glauca: interphase trophocytes and a mitotic metaphase diploid trophocyte. Scale bars: 10 μm.