The male and female genitalia and accessory glands of five British species of pseudoscorpion of the genus Chthonius are described. The taxonomic significance of the genitalia is considered.


The male and female genitalia of five species representing the genus Chthonius are fundamentally similar in form. However minor differences do occur which are of possible taxonomic significance at both the sub-generic and specific levels. Thus, the two species C. kewi and C. tetrachelatus of the sub-genus Ephippiochthonius have a number of characters in common which differ from those of the remaining three species, C. ischnocheles, C. tenuis and C. orthodactylus of the subgenus Chthonius ( Other genital characters can be used to separate the five species.

Such small differences in the genitalia suggests that spermatophore formation and deposition in the four species C. tenuis, C. tetrachelatus, C. kewi and C. orthodactylus is not different from that of C. ischnocheles (Legg, 1973). What differences that do occur, for example, the thickening of the roof of the medial diverticulcum, size of the males and the pheromone produced by the lateral glands, probably are aids to species isolation.