Key to stages of Sennertionyx manicati (Giard, 1900)

1. With 4 pairs of legs; Claparède organs absent; genital opening and papillae present (1 or 2 pairs); hysterosoma with 12 pairs of setae (f 2 and h 3 present)................................................................................. 2

–. With 3 pairs of legs; a pair of Claparède organs (Fig. 21B) present; no genital opening or papillae; hysterosoma with 10 pairs of setae (f 2 and h 3 absent)............................................................................ larva

2. Idiosoma saccate, soft bodied (Fig. 1); gnathosoma developed, chelicerae chelate; anal attachment organ absent; genu I with 2 solenidia (Fig. 3A).................................................................................... 3

–. Idiosoma dorsoventrally flat, highly sclerotized (Fig. 13); gnathosoma reduced, chelicerae absent (Fig. 14); ventral hysterosoma with an anal attachment organ (Fig. 14); genu I with 1 solenidion (Fig. 16A)......................... deutonymph

3. With 2 pairs of genital papillae (Fig. 2); ventral setae 3a and 4a present (Fig. 2); solenidion ω 3 on tarsus I present (Fig. 3A); femur IV and tibia IV with setae (Fig. 3D)................................................................. 4

–. With 1 pair of genital papillae (Fig. 18); ventral setae 3a and 4a absent (Fig. 18); solenidion ω 3 on tarsus I absent (Fig. 20A); femur IV and tibia IV nude (Fig. 20D)............................................................ protonymph

4. Genital folds present (Fig. 2); with either spermatheca (Fig. 2) or aedeagus (Figs 5, 24B)............ (adult)........... 5

–. Genital folds absent (Fig. 10); without spermatheca or aedeagus (Fig. 10)................................. tritonymph

5. Aedeagus present (Figs 5, 24B); without a spermatheca; anal suckers present (Fig. 6); adanal setae absent; tarsus IV with 2 suckers (Fig. 8D).............................................................. adult male...............6

–. Aedeagus absent but with a spermathecal (Fig. 2); anal suckers absent; 3 pairs of adanal setae present (Fig. 2); tarsus IV without suckers (Fig. 3D)............................................................................. dult female

6. One side of leg III enlarged (Fig. 8C)...................................................... heteromorphic male

–. Leg III not enlarged but similar to leg IV (Fig. 8E)............................................homeomorphic male