This is a complicated genus, that I have actually done a lot of field work on. The species of Hyperomyzus sensu stricto are invasive in North America, living on Sonchus (sowthistle) and Ribes. The species of Hyperomyzus (Neonasonovia) are mostly Nearctic in origin, living on various Asteraceae and Ribes. I have collected many samples of the latter subgenus, and have not been able to make heads or tales of the species-level taxonomy. See the link to subgenus Neonasonovia for a brief report of my 2018 analyses of my samples.
Hyperomyzus pallidus Hille Ris Lambers
When I first read about this species in Hille Ris Lambers’ original description I was new to aphids and was getting up to speed by reading everything about them I could find. In his work he wrote about this species being distinct from Hyperomyzus lactucae (L.), living on the lower leaves of the same Sonchus host plants as H. lactucae. I was amazed and wondered whether Hille Ris Lambers really knew what was going on.
Since then, I have come to understand that ‘Lambers,’ as I call him, was rarely wrong. Here is the aptera of H. pallidus, sure enough living on the lower leaves of the same species of Sonchus on which H. lactucae is commonly found in central Washington. Hyperomyzus pallidus is introduced from Europe and common in North America. I have material from Washington, and Ontario, Canada.