Key to adult Anacroneuria of Reserva Floresta Adolpho Ducke, A. amazonica known only from females

1– Pronotum largely dark brown laterally and narrowly dark brown posteriorly, medially light yellow (Figs 6–7); head predominantly dark brown with ocelli separated by twice their width (Fig. 8). Aedeagus scletotized, apex truncate (Figs. 30–32). Penial armature with hooks short, folded for low (Fig. 31). Female sternum eight with median notch deeper and paramedian lobes longer and lateral lobes small (Fig. 33). ................................ Anacroneuria manauensis

– Pronotum light brown to yellow laterally, medially light yellow, reaching the posterior margin (Figs. 1–2, 11–12); head predominantly yellow to whitish in alcohol with ocelli separated by one time their width (Figs. 3, 13); aedeagus less scletotized, apex acuminate (Figs. 20–22, 40-42). Female sternum eight with median notch shallower or deeper than sublateral notch (Figs. 23, 43 and 45) ................................................................................................................... 2

2– Pronotum with narrow and distinct lateral brown stripe (Fig. 13); apex of aedeagus trilobed (Figs. 40–41). Penial armature with hooks short, folded slightly for low (Fig. 41). Female sternum eight with lateral lobes longer than paramedian lobes (Fig. 43) .......................................................................................................... Anacroneuria marlieri

– Pronotum uniformly colored, lacking lateral stripe or with lateral stripes composed of lightly pigmented rugosities (Fig. 3); aedeagal apex with a distinct medial lobe (Figs. 20–21). Female sternum eight with lateral lobes equal to or shorter than paramedian lobes (Figs. 2) ........................................................................................................................ 3

3– Pronotum with slightly darker lateral stripe (Fig. 3). Apex of aedeagus with a wavy medial keel, with internal depression and two distinct, membranous vesicles, penial armature with hooks long, directed inward (Fig. 21). Female sternum eight with four lobes of equal length (Fig. 23) ................................................... Anacroneuria minuta

– Pronotum uniformly colored, without darker lateral stripe. Female sternum eight with lateral lobes smaller than paramedian lobes (Fig. 46) ..................................................................................................... Anacroneuria amazonica