To Munro's conjecture, which has been accepted by Diels (1923), S. B. Smith (1942), Bailey (1947), Büchner (1956), Martin (1959), and M. F. Smith (1982), there is a serious, possibly a fatal, objection: the genitive plural of hiems is a grammarians' figment and never occurs in classical Latin (TLL s.v. 2773.84); while Lachmann's conjecture is palaeographically improbable. Read ad gelidas rigidasque pruinas; rigidas was omitted by haplography, a fecund source of corruption, and hiemis then supplied from the context to repair the metre. Cf. 2.431 denique iam calidos ignis gelidamque pruinam, 2.521 hinc flammis Mine rigidis infesta pruinis, and, for the collocation of the two adjectives, 2.858 nec frigus neque item calidum tepidumque uaporem.