Abstract
The poplar admiral, Limenitis populi jezoensis Matsumura usually becomes the third-instar larvae before winter comes, and passes the winter by the third-instar larvae. However, it was discovered that the some larvae had grown up to the fourth-instar larvae before winter came by the poplar admiral in the Chubu region, Honshu, Japan. The fourth-instar larvae appeared almost every year and they showed up regardless of the day length. So, it was guessed that this species or the species in this region was a population with the gene generated twice or more a year.
