How do I reduce the development rate of a male Periphobas sp. cocoon without killing it

I have a male Periphobas pupa that's been a pupa slightly longer than a week, while the female has been in pupation for a couple days. I would like to reduce the development rate of the male so it would hatch more or less at the time the female eclodes, just in case there aren't male Periphobas alive in the area when the female is an imago. Pupation time varies from 2 to 5 months by the way, depends greatly on diet. They've been reared on rose (around the last larval stage), guava (more or less through L1 to the last instar), jackfruit (for around a week before the last larval stage or two) and hibiscus (around the last instar as well).