That the thirteenth Idyll of Theocritus and the Hylas episode in the first book of Apollonius are not independent of each other was perhaps first pointed out by Casaubon, who supposed T. to be the earlier of the two. The opposite view was upheld, whether for the first time or not I do not know, by Wilamowitz in his lectures, and it was assumed, without much argument, by his pupil G. Knaack, who presently defended it, with little more, against an attack by G. Türk. Gercke and Susemihl were persuaded, and later on Wilamowitz himself touched briefly on the matter. Legrand, who had doubted before, remains unconvinced, and Cholmeley, to whose chronology this theory was disastrous, took shelter behind the unsubstantial shades of Antimachus and Philetas. In Italy, G. Perrotta has supported Wilamowitz's view, but L. Bignone says that the problem is insoluble. I have myself no doubt that Wilamowitz was right, but the arguments employed have not been very cogent, and, as the evidence has not been well set out, it may be useful to outline it here and to add a little to it.