This section presents genitalia illustrations of species in the family Geometridae. The genitalia illustrations are line drawings and cover the species where the genitalias may be useful for the identification. The genital differences of the four Nychiodes taxa recorded from the Iberian Peninsula are very small, and the wing pattern is so similar and variable, that it is not suitable for identification. Furthermore there is no overlap in the distribution of the four taxa. The most recent described of the four taxa, Nychiodes notarioi, has the largest distribution and occurs in the best investigated part of the Peninsula. The main genital characters for this group are the distal part of the male genitalia valves and the signum, ductus bursae and lamella antevaginalis of the female genitalia.Keywords: genitalia illustrations; Geometridae; Iberian Peninsula; Nychiodes