The syntypes of Siphonophora fragariae var. Immaculata Riley were rediscovered in the aphid collection of the United States of America National Museum of Natural History. The name (S. fragariae Immaculata) previously being largely lost and forgotten, we here establish it as the senior synonym of Macrosiphum euphorbiae (Thomas). Reversal of precedence can be validated, however, and we establish S. fragariae Immaculata as a nomen oblitum and M. euphorbiae a nomen protectum with respect to each other. In uncovering the original description of the Riley species, we also found a description of Aphis rapae var. laevigata Riley. We have not found A. rapae laevigata anywhere else in the literature nor have we found any type specimens. Based on Riley's succinct description and host plant identity, we consider it a nomen dubium synonym of Myzus persicae (Sulzer). Because the short articles publishing the two aphid names have been missing from taxonomists' libraries, they are transcribed in their entirety.