Male genital structures of Cylindrotoma distinctissima (Meigen, 1818) (A–M), in comparison to C. americana Osten Sacken, 1865 (N–P) A terminalia, dorsal view B terminalia, ventral view C terminalia, lateral view; D Apical lobe of the gonocoxite (Japan) E apical lobe of the gonocoxite (Finland) F shape of the gonostylus caudal view (Japan) G shape of the gonostylus caudal view – Finland H aedeagus complex, dorsal view I aedeagus complex, ventral view J aedeagus complex, lateral view K tip of the aedeagus L shape of the aedeagus (Japan) M shape of the aedeagus (Finland); C. americana Osten Sacken N apical lobe of the gonocoxite O shape of the gonostylus caudal view P shape of the aedeagus. Abbreviations: ae – aedeagus; al – gonocoxite apical lobe; eja – ejaculatory apodeme; gc – gonocoxite; gs – gonostylus; ib – interbase; pm – paramere; sp – sperm pump; s9 – sternite 9; t9 – tergite 9; vl – gonocoxite ventral lobe.