Enochrus Thomson

Byttebier, Barbara & Torres, Patricia L. M., 2009, Description of the preimaginal stages of Enochrus (Hugoscottia) variegatus (Steinheil, 1869) and E. (Methydrus) vulgaris (Steinheil, 1869) (Coleoptera: Hydrophilidae), with emphasis on larval morphometry and chaetotaxy, Zootaxa 2139, pp. 1-22 : 16

Key to the larval instars of Enochrus Thomson

1 Lateral margins of mentum without stout setae ( Figs. 14–15 ). Mandibles with 2 setae (MN1, MN5) ( Figs. 11–12 ). Cephalic capsule without row of setae in between PA6 and PA7 ( Figs. 4 , 8 ) .................................................... Instar I

1’ Lateral margins of mentum with stout setae ( Figs. 22–25 ). Mandibles with more than 2 setae (usually more than 6) distributed along the lateral margin ( Figs. 19–20 ). Cephalic capsule with row of 1–6 setae in between PA6 and PA7 ( Figs. 21 ) ....................................................................................................................................................................... 2

2 Lateral margins of mentum with 2 stout setae. Tibiotarsus without anteroproximal pore ............................... Instar II

2’ Lateral margins of mentum with 3–4 (occasionally 5–6) stout setae ( Figs. 22–25 ). Tibiotarsus with anteroproximal pore ( Fig. 28 ) ................................................................................................................................................... Instar III

Figures

FIGURES 11 – 17. Enochrus variegatus, first-instar larva: 11, left mandible, dorsal view; 12, right mandible, dorsal view; 13, right antenna, dorsal view; 14, labium, dorsal view; 15, labium, ventral view; 16, left maxilla, dorsal view; 17, right maxilla, ventral view. Scale bars = 0.05 mm.

FIGURES 3 – 6. Enochrus variegatus, first-instar larva: 3, head capsule, lateral view; 4, head capsule, dorsal view; 5, frontoclypeus, dorsal view; 6, head capsule, ventral view. Scale bars: Figs. 3 – 4 = 0.1 mm, Fig. 5 = 0.05 mm, Fig. 6 = 0.1 mm.

FIGURES 7 – 10. Enochrus vulgaris, first-instar larva: 7, head capsule, lateral view; 8, head capsule, dorsal view; 9, frontoclypeus, dorsal view; 10, head capsule, ventral view. Scale bars: Figs. 7 – 8 = 0.1 mm, Fig. 9 = 0.05 mm, Fig. 10 = 0.1 mm.

FIGURES 22 – 25. Enochrus variegatus, third-instar larva: 22, labium, dorsal view; 23, labium, ventral view. Enochrus vulgaris, third-instar larva: 24, labium, dorsal view; 25, labium, ventral view. Scale bars = 0.05 mm.

FIGURES 18 – 21. Enochrus vulgaris, first-instar larva: 18, right antenna, dorsal view. Enochrus vulgaris, third-instar larva: 19, left mandible, dorsal view; 20, right mandible, dorsal view; 21, head capsule, dorsal view. Scale bars: Figs. 18 – 20 = 0.05 mm, Fig. 21 = 0.1 mm.

FIGURES 26 – 29. Enochrus variegatus, legs of first-instar larva: 26, prothoracic leg, anterior view; 27, prothoracic leg, posterior view. Enochrus vulgaris, legs of third-instar larva: 28, metathoracic leg, anterior view; 29, metathoracic leg, posterior view. Scale bars = 0.05 mm.