Production of First-instar Defenders by the Hormaphidid Gall-forming Aphid Hamamelistes cristafoliae Living Anholocyclically on Betula maximowicziana

Hamamelistes cristafoliae MONZEN, 1954 is a hormaphidid aphid that induces cockscomb-shaped galls on leaves of Betula maximowicziana. Mansakia betulina makabae INOUYE, 1963 was treated as a junior synonym of H. cristafoliae. Morphological characters of H. cristafoliae were compared with those of other Hamamelistes species. H. cristafoliae is monoecious and exclusively parthenogenetic on Betula maximowicziana. First-instar nymphs produced in the galls in summer exhibited defensive behavior against predators. Galls of this species frequently contained a drepanosiphid aphid, which was considered as an inquiline.