~ Date of birth unknown ~
Other then some artworks I was unable to find more about P. Silex, which is most likely a pseudonyme.
The book L’ecrin du rubis ou les Délices des dessous was illustrated by Silex, the front cover is from a different artist. The same book was also illustrated by Cheri Herouard in a publication from 1939.
L’écrin du rubis ou les Délices (1932)