If blood flukes were to exhibit strict cophyly over millions of years, you would predict that blood flukes would:

Cophyly is the process when a parasite and host speciate together.

If blood flukes were to exhibit strict cophyly over millions of years, you would predict that blood flukes would - evolve in a manner that is exactly in the same way as the evolution of their host. Evolution is a process when something evolves over a period of time.