This species is a favorite beetle in the USA and called the 'Unicorn'.   Each and every male is different in the markings on its elytra (Shell) with some being heavily spotted and others random markings here and there! They range in size from normal sized males measuring 35mm from tip of horn to end of body, to the big guys over 60mm with nicely developed head horns.  Get yours now because they are hard to come by!