Key to females of the subgenus Parancistrum, based on vulvae and external morphological characters

1 Vulvae markedly asymmetric, with lateral hump (lh) strongly protruding distally, by far outreaching central (ch) and mesal (mh) humps, and operculum (o) (Fig. 22).......................................................... M. serratum

- Vulvae more or less symmetric.......................................................................... 2

2 Vulvae with lateral (lh) and mesal humps (mh), but without central hump at apical margin of bursa..................... 3

- Vulvae with lateral (lh), mesal (mh) and central humps (ch) at bursal apical margin (Figs 55–57)...................... 4

3 Bursa somewhat constricted in its distal part (Fig. 40); operculum shorter than bursa....................... M. turcicum

- Walls of bursa more or less straight; operculum equal in height to bursa (Fig. 8)........................... M. curvifolii

4 Vulva more gracile, mesolaterally strongly compressed, with a visibly concave median side lobe (Fig. 57); bursal hyaline pro- trusions (bl) very long, ca 1/3 of base-to-apex height (Fig. 17)................................... M. genezarethanum

- Vulva more robust, mesolaterally less strongly compressed, with a flat, mesal side lobe; bursal hyaline protrusions shorter than 1/3 of base-to-apex height.............................................................................. 5

5 Subanal scale triangular, protruding behind rear contour of anal valves; bursa of vulva more asymmetric, its lateral hump (lh) much wider than mesal one (mh) (Fig. 56)...................................................... M. tenenbaumi

- Subanal scale narrowly rounded, not protruding behind rear contour of anal valves; bursa of vulva less strongly asymmetric, lateral hump (lh) slightly wider than mesal one (mh) (Figs 44, 54)................................. M. arcuatum sp. n.