Key to Mexican ’ nassa ’ species complex of Amphibolips

1. Mesoscutellum rounded posteriorly (Figs 37–38)................................................ ’ niger’ complex in Mexico [galls rounded, with very dense furry surface (Fig. 46)], and all known Amphibolips species from USA and Panama

- Mesoscutellum with posteromedian emargination (Figs 10, 32, 39–40)........................................... 2

2. Posterior sides of mesoscutellum, aside of posteromedian impression, strongly emarginate, dorsally V-shaped, with sharp horn projection in lateral view (Figs 40–41)...................................................... palmeri and dampfi

- Posterior part of mesoscutum more or less impressed but dorsally not V-shaped, without sharp horn projection in lateral view (Figs 10, 32, 39)................................................................................. 3

3. Heavy dark stripe along anterior margin of forewing interrupted by clear unpigmented cross band in cell delimited by R1+Sc and Rs+M (Fig. 34)............................................................................. 4

- Heavy dark stripe along anterior margin of forewing uninterrupted in cell delimited by R1+Sc and Rs+M (Fig. 14)........ 5

4. F3 1.3 times as long as F4; gall elongate, spindle-shaped, with hard and lignified parenchima (Figs 42–43), on Q.castanea (= Q. serrulata) and Q. mexicana ....................................................................... nassa

- F3 equal in length to F4 (Fig. 5); gall rounded, with soft and spongious parenchima (Figs 18–20), on Q. crassifolia, Q. cras- sipes and Q. candicans .................................................................. hidalgoensis n. sp.

5. Head quadrangular in front view, anterior tentorial pits small, distance between them 7.0 times as large as diameter of pit (Fig. 1); scutellar foveae as long as broad (Fig. 9); forewing with short dense cilia on margin; metasoma black; gall rounded, only slightly elongate to apex, with soft and spongious parenchima (Figs 15–17), on Q. eduardi ............ zacatecaensis n. sp.

- Head rounded in front view, anterior tentorial pits large, distance between them only 3.0–3.5 times as large as diameter of pit (Fig. 47); scutellar foveae longer than broad (Fig. 48); forewing without cilia on margin; metasoma dark brown; gall elongate, spindle-shaped, with hard parenchima (Figs 44–45), on Q. eduardi .......................................... fusus