Macrosiphum cockerelli Hottes 1950 = Macrosiphum rudbeckiarum (Cockerell 1903)

Hottes (1949) gave a very full description of an aphid from Rudbeckia that he identified as Macrosiphum rudbeckiarum (Cockerell) . However,. Hottes (1950) subsequently applied the name M. cockerelli to his aphid, in deference to M.A. Palmer, who had pointed out to him that the type alata of rudbeckiarum had fewer rhinaria. However there are no other significant differences, and no alatae with such low rhinarial numbers have since been collected, so it is highly unlikely that there are two separate species.