Konchuki

Anri Kajimi is a junior-high boy who loves Insects so much that he doesn't have any human friends. One day, he suddenly found a naked girl in his house. She told him her name is Makiri Oka, and that she is a Konchuki (insect girl), with a mix of human and insect characteristics. And that she had come from 100 years in the future to fulfill Anri's wish. And that wish is for "Anri to mate with me"…
(Source: ComicWalker, translated)