Karyotypes of Chthonius (Chthonius) males based on postpachytene and metaphase I. AC. (C.) alpicola (2n = 21, X0) (large black spot on the first autosome pair represents overlap with the sperm) BC. (C.) carinthiacus (2n = 35, X0) CC. (C.) ischnocheles, cytotype I (2n = 31, X0) DC. (C.) ischnocheles, cytotype II (2n = 35, X0) EC. (C.) raridentatus, cytotype I (2n = 29, X0) FC. (C.) raridentatus, cytotype II (2n = 29, X0) GC. (C.) rhodochelatus, cytotype II (2n = 35, X0). Asterisks indicate chromosome overlaps. Scale bar = 10 µm.