It is generally agreed that Philo’s allegorical treatises are his most difficult works. In order to read them, it is necessary to understand the method of his often labyrinthine exegesis. Much research has been done of this subject, but general agreement has not been reached. In the present paper I will examine the structure of the treatise De agricultura and show how it demonstrates various features of Philo’s exegetical method. Particular attention will be paid to the theory of M. Adler, who many years ago argued for an evolutionary view of how Philo wrote the sequence of treatises in his Allegorical commentary.