1	Cauda tongue-shaped, with 3–9 setae, without sclerites on dorsum abdominal segments I, II, and III. Secondary sensoria on antennal segment III (4–9), IV (0–3). DBIII 0.07–0.12 (Figure 6C). Ratios PT/B 1.9–3, SIPH/CA 1.1–1.8. (Figure 7E)	Aphid monardae
–	Cauda constricted, sometimes with sclerites on dorsum of abdominal segments I, II, and III	2
2	Antenna VI PT/B 2.1–3.6. Secondary sensoria on antennal segment III (4–10) DBIII 0.04–0.07 (Figure 6B). Sometimes with transverse sclerites on dorsum of all abdominal segments (Figures 7B–C). Ratio SIPH/CA 1.1–2.3. Polyphagous	Aphid gossypii
–	Antenna VI PT/B 1.9–2.3. Secondary sensoria on antennal segment III (7–10) and IV (0–2) (Figure 6F). Sometimes with transverse sclerites on dorsum of all abdominal segments (Figure 7D). Ratio SIPH/CA 0.9–1.5. On Hylotelephium spp.	Aphid sedi
–	Antenna VI PT/B 2.2–2.9. Secondary sensoria on antennal segment III (2–8) (Figure 6E). Never with sclerites on dorsum of abdomen (Figure 7G). Ratio SIPH/CA 1.8–2.1. On Oenothera spp.	Aphid oestlundi