Key to the known species of the genus Enochrus from Japan (all instars) 1

1. Secondary sensilla between PA6 and PA7 absent (Fig. 13A); mandible with two setae (MN1 and MN5) (Figs. 14 B–C); distal part of outer face of stipes with two setae (MX 5 and MX 6) (Figs. 14 D–E); lateral face of mentum without stout setae (Figs. 14 F–G). First instar. ............................................................................................................................... 3

– Secondary sensilla between PA6 and PA7 present (Fig. 18); mandible with more than two setae (Figs. 17 C–D); distal part of outer face of stipes with three setae (Figs. 17 E–F); lateral face of mentum with stout setae (Figs. 17 G–H). ............................................................. 2

2. Lateral face of mentum with two stout setae (Figs. 15 H–I). Second instar. ................... 4

– Lateral face of mentum with more than three setae (usually four to five) (Figs. 17 G–H). Third instar. ..................................................................................................................... 5

3 Prolegs with stout spines, the spines strongly curbed to apex (Figs. 28 A–D). .................. ..................................................................... E. (Holcophilydrus) simulans (Sharp, 1873)

– Prolegs with slender spines, the spines not strongly curved to apex (Figs. 28 E–G). ......... ........................................................................... E. (Methydrus) japonicus (Sharp, 1873)

4. Inner face of stipes with more than six stout setae (Figs. 24 E–F); prolegs with slender spines (Fig. 28F). .............................................. E. (Methydrus) japonicus (Sharp, 1873)

– Inner face of stipes with five stout setae (Figs. 15 F–G); prolegs with stout spines (Fig. 28B). .......................................................... E. (Holcophilydrus) simulans (Sharp, 1873)

5. Inner face of stipes with more than six stout setae (Figs. 26 E–F); prolegs with slender spines (Fig. 28G). ............................................. E. (Methydrus) japonicus (Sharp, 1873)

– Inner face of stipes with five stout setae (Figs. 17 E–F); prolegs with stout spines (Figs. 28 C–D). .............................................................................................................................. ............ E. (Holcophilydrus) simulans (Sharp, 1873) and E. (H.) umbratus Sharp, 1884