The parasitoid Hyposoter rhodocerae (Rondani, 1877) is a specialis that only parasitize the caterpillars of the genus Gonepteryx (G. cleopatra & G. rhamni). Only one egg is laid inside the body of the caterpillar. Before hatching the parasitoid larva mummifies the body of its host and will become a pupa inside.
The big question is; how does Hyposoter rhodocerae overwinters, because Gonepteryx cleopatra overwinters as a butterfly?
Remarks and identification by Dr. Mark R. Shaw
Le Citron de Provence
Cleopatra
Fleeting wonders
Butterflies of France 
Lepidoptera & their ecology
Matt's European Butterflies
Anything but common 
L'Ecaille Matrone 
Lépi'Net