Anyone who has ever heard of the Hercules beetles, or has seen one, was certainly surprised and fascinated by such grandeur. For the neophyte collector of beetles, the genus Dynastes brings images of stupendous, attractive insects that show an important sexually dimorphism, with only males exhibiting the characteristic horns, and are grateful subjects to have in his/her collection. For the specialist, the 22 species and subspecies constitute a challenge in terms of research into differences and similarities making it possible to distinguish and define these species. The genus Dynastes contains species desired by breeders and more and more amateur entomologists and specialists start to breed beetles.
The males and females of all 22 known Dynastes are illustrated with photos of several examples (wild and bred), if possible. However, this work must not be considered as a revision of the genus Dynastes, but as a documentation and as an iconographic catalogue based on the photographic illustrations of all species, subspecies and forms documented until today. To define species, the authors not only focus our attention on the thoracic and cephalic horns of major males but also on the shape of the total body, on minor details on pronotum and elytra and on the differences in aedeagus. The identification of minor males as well as the females remains very difficult. Concerning females, the scutellum and the color of the last 1/3 of the elytra can serve as general guidelines but not as characteristics for a specific species because exceptions and similarities between species occur quite often.