
If you have questions about the conjugation of рогач or Russian nouns in general, you can practice and get feedback from a professional tutor.
Кажется, у этого вашего мальчишки жук-рогач в кармане.
I think that boy of yours has a stag beetle in his pocket.
Вначале изучал "Ретулус Дидиери", или жука-рогача.
At first l studied the Rhaetulus didieri, or stag beetle.