Host-range and host-specificity tests were performed with Cybocephalus flavocapitis T. R. Smith (Coleoptera: Cybocephalidae) and Cybocephalus nipponicus Endr$ddot{o}$dy-Younga (Coleoptera: Cybocephalidae), two biological control candidates against the invasive cycad aulacaspis scale, Aulacaspis yasumatsui Takagi (Hemiptera: Diaspididae). Seventeen native scale species plus the invasive A. yasumatsui scale were tested in growth chambers using no-choice tests and hosts suitable for each of the two predatory beetles. The results revealed that the two Cybocephalus beetles, one imported species from Thailand and one native species, both fed on relatively similar scale prey species. Additionally, the adult beetles of these two species oviposited only on Diaspididae scales. The results showed that both Cybocephalus beetles may share a similar host niche in Taiwan.