Key to females of species of Xylocopa (Neoxylocopa) recorded from the Amazon River basin of South America

1. Frons with a stout central tubercle immediately adjacent to ocelli, or with two horn-like projections immediately adjacent to ocelli....................................... 2

— Frons flat adjacent to ocelli..................................................... 3

2(1). Frons with a stout central tubercle; the median ocellus bisecting the front of the tubercle...................................................... X. (N.) frontalis (Olivier)

— Frons with a transverse ridge ending on either side in a more or less distinct horn-like projection immediately adjacent to the lateral ocelli; median ocellus located well below carina on flat portion of frons.................................... X. (N.) fimbriata Fabricius

3(1). Mesosomal pubescence yellow, orange, or reddish-orange............................. 4 — Mesosomal pubescence black or dark brownish-black................................ 7

4(3). Mesosomal pubescence bright yellow............................................. 5 — Mesosomal pubescence orange or reddish-orange................................... 6

5(4). Body massive, overall body length 21.8 to 29.6 mm ......... X. (N.) grisescens Lepeletier — Body smaller, overall body length 16.4 to 17.6 mm ............. X. (N.) cearensis Ducke

6(4). Pubescence of first metasomal tergite orange, at least in part....... X. (N.) similis Smith — Pubescence of first metasomal tergite entirely black....... X. (N.) aurulenta (Fabricius)

7(3). Wing pigmentation clear; wing surface sometimes with metallic iridescence............. 8 — Wings pigmentation dark brownish-black; wing surface often with metallic iridescence.... 9

8(7). Wings with very faint, feeble iridescence; scutellum broadly rounded and lacking a transverse ridge........................................... X. (N.) aeneipennis (De Geer)

— Wings with strong, brilliant gold-coppery iridescence; scutellum medially with a broad, sharply angled transverse ridge............................ X. (N.) orthogonaspis Moure

9(7). Wings with greenish-blue, golden-green, or green iridescence........................ 10 — Wings with violet iridescence................................................... 11

10(9). Wings with uniform brilliant green or golden-green iridescence.................................................................. X. (N.) suspecta Moure and Camargo

— Wings with dull greenish-blue iridescence; iridescence bluer towards base of wing and becoming somewhat brighter greenish towards apices of wings... X. (N.) amazonica Enderlein

11(9). Mesonotum clothed in black pubescence except for a median triangular smooth and glossy area; tegulae black............................................................. 12

— Mesonotum almost entirely glabrous and glossy, with limited amounts of black pubescence; tegulae orange or reddish-brown.......................... X. (N.) tegulata Friese

12(11). Overall body size larger, body length 20.5 to 23.0 mm......... X. (N.) hirsutissima Maidl — Overall body size smaller, body length 17.0 to 18.6 mm ........ X. (N.) carbonaria Smith