Key to species of the Periphyllus koelreuteriae complex (Apterous viviparous females) 1. A smaller dark brown dorsal spot extending from head to abdominal tergites of live specimens, reticulations are usually less than 2. Mainly distributed in subtropical highland region. Obligate feeding on K. bipinnata, Molecular diagnosis: nucleotides 312 C, 492 A, 594-595 TC.................................................... P. guangxuei Li & Huang sp. nov. - Three black or dark brown thorax and dorsal spots of live specimens, reticulations are usually greater than 2, feeding on K. paniculate ............................................................................................2 2. Also feeding on K. bipinnata. Dorsal spots on abdominal tergites interconnected to cauda. Mainly distribute in subtropical humid region. Molecular diagnosis: nucleotides 312 G, 492 T, 594-595 CT............. P. blackmani Li & Huang sp. nov. - Obligate feeding on K. paniculate. Dorsal spots on abdominal tergites not interconnected to cauda. Molecular diagnosis: nucleotides 312 A, 492 C, 594-595 TT.............................................................. P. koelreuteriae

Published as part of Li, Qiang, Wu, Liying, Cheng, Zhentao, Liu, Zhixiang & Huang, Xiaolei, 2022, Two new cryptic species within Periphyllus koelreuteriae (Hemiptera: Aphididae) feeding on Koelreuteria (Sapindaceae) in China, pp. 220-238 in Zootaxa 5183 (1) on page 231, DOI: 10.11646/zootaxa.5183.1.17, http://zenodo.org/record/7070146