Key to genera and species of Heatherellidae (adults)

1. Peritremes absent (Figs 1, 36); female with setae st3–4 on common shield or st 3 in soft cuticle; dorsal shields sexually dimorphic: female (Figs 2, 15) with podonotal-mesonotal shield; males (Fig. 13) with podonotal shield and three mesonotal shields (one medial, two lateral); female latinotal shield undivided; ventral seta JF3 reduced, on anal rim (Fig. 1); male st5 on separate shield from st1–4 (Fig. 12) ... Heatherella ................................................................. 2

- Peritremes present, short (Figs 16, 37); female with st3 and st4 on separate platelets; dorsal shields monomorphic: both sexes with podonotal-mesonotal shield (Fig. 17); latinotal shield divided into podonotal and mesonotal regions; ventral seta JF3 normal, removed from anus (Fig. 16); male st5 on intercoxal shield (Fig. 24)........................... Aheatherella mira

2. Dorsal setae somewhat thickened, barbed, without ciliate crests, dissimilar to marginal (r -R) setae (Fig. 15); seta z2 absent; marginal setae duplicated (22 pairs); anterior opisthogastric setae simple; 8–9 pairs of submarginal protuberances (always lacking protuberance P -s6, between s6 and S1); protuberance posterior to seta s5 a raised pustule, different from other protuberances............................................................................................. 3

- Dorsal setae bifurcate, with ciliate crests, similar to marginal (r -R) setae (Fig. 2); seta z2 present; marginal setae highly hypertrichous (> 24 pairs); opisthogastric setae all short, bulbous and barbed; ten pairs of submarginal protuberances (with protuberance P -s6 between s6 and S1); protuberance posterior to seta s5 not obviously different from other protuberances................................................................................................ Heatherella osleri

3. Adult sternal shield (bearing st2) rounded anteriorly in both sexes, without endopodal elements; dorsum lacking protuberance P -s4 between setae z4 and s4; seta z6 posterior to s6, seta Z1 posterior to S1; seta z5 placed obliquely to seta j5; male with seta av1 on genu II unmodified............................................... Heatherella acanthocharis Walter, 1997

- Adult sternal shield (bearing st2) angular anterior corners in both sexes, endopodal elements fused to shield; dorsum with protuberance P -s4 (Fig. 15); seta z6 anterior to s6, seta Z1 anterior to S1; seta z5 almost transversely aligned with seta j5; male with seta av1 on genu II modified into small blunt spur........................... Heatherella callimaulos Walter, 1997