Uroleucon cirsii explained

Uroleucon cirsii, the large thistle aphid, is a species of aphid in the family Aphididae.

Book: Arnett . Ross H. Jr.. 2000. American Insects: A Handbook of the Insects of America North of Mexico. CRC Press. 2nd. 0-8493-0212-9.
Foottit . R.G.. Halbert . S.E.. Miller . G.L.. Maw . E.. Russell . L.M.. 4. 2006. Adventive aphids (Hemiptera: Aphididae) of America north of Mexico. Proc. Ent. Soc. Wash.. 108. 583–610.
Skvarla . Michael J.. Halbert . Susan E.. Foottit . Robert G.. Jensen . Andrew S.. Maw . Eric. Miller . Gary L.. 4. 2017. An Update to the Adventive Aphids (Hemiptera: Aphidoidea) of America North of Mexico, with Notes on Intercepted Species. Proceedings of the Entomological Society of Washington. 119. 90–111. 10.4289/0013-8797.119.1.90. 91004743.

Further reading