Agraphydrus Régimbart, 1903

Minoshima, Yûsuke & Hayashi, Masakazu, 2011, Larval morphology of the Japanese species of the tribes Acidocerini, Hydrobiusini and Hydrophilini (Coleoptera: Hydrophilidae), Acta Entomologica Musei Nationalis Pragae (suppl.) 51, pp. 1-118 : 17

Genus Agraphydrus Régimbart, 1903

( Figs. 1A , 7–12 , 44A , 45A )

Diagnosis. The genus Agraphydrus is similar to other genera of the Japanese Acidocerini , but is distinguished from them by the following characters: (1) head capsule with long scale-like setae ( Figs. 7 , 9A , 10 , 12C ); (2) nasale with distinct teeth, not serrate or smooth ( Figs. 7C , 10C ); (3) antennal sensorium (SE1) rather long ( Figs. 8A , 11A ); (4) mandibles asymmetrical, left mandible with one inner tooth, right mandible with two teeth ( Figs. 8 B–C, 11B–C); (5) abdominal segments with spinose prolegs ( Figs. 12 A–B).

Figures

Fig. 1. Habitus of the third instar larvae of Acidocerini and Hydrobiusini. A – Agraphydrus narusei (Satô, 1960), dorsal and lateral view; B – Enochrus (Holcophilydrus) simulans (Sharp, 1873), dorsal view; C – E. (H.) umbratus Sharp, 1884, dorsal view; D – E. (Methydrus) japonicus (Sharp, 1873), dorsal view; E – Helochares (Helochares) pallens (MacLeay, 1825), dorsal view; F – H.(Hydrobaticus) nipponicus Hebauer, 1995, dorsal view; G – Hydrobius pauper Sharp, 1884, dorsal and ventral view.

Fig. 7. Head capsule of Agraphydrus narusei (Satô, 1960), first instar. A – dorsal view; B – ventral view; C – detail of anterior margin of head capsule, dorsal view.

Fig. 8. Head appendages of Agraphydrus narusei (Satô, 1960), first instar. A – antenna, dorsal view; B–C – mandibles, dorsal view; D – maxilla, dorsal view; E – maxilla, ventral view; F – labium, dorsal view; G – labium, ventral view.

Fig. 9. Agraphydrus narusei (Satô, 1960), third instar.A – head, dorsal view; B – spiracular atrium, dorsal view.

Fig. 10. Head capsule of Agraphydrus narusei (Satô, 1960), third instar.A – dorsal view; B – ventral view; C – detail of anterior margin of head capsule, dorsal view.

Fig. 11. Head appendages of Agraphydrus narusei (Satô, 1960), third instar.A – antenna, dorsal view; B–C – mandibles, dorsal view; D – maxilla, dorsal view; E – maxilla, ventral view; F – labium, dorsal view; G – labium, ventral view.

Fig. 12. Agraphydrus narusei (Satô, 1960).A–B – prolegs, ventral view:A – first instar; B – third instar. C–D – shape of setae, dorsal view: C – median part of parietale, third instar, dorsal view; D – thoracic segments, first instar, dorsal view. Seta on PA8 and PA13 missing. Photographs were taken with compound light microscope.

Fig. 44. Prosterna of Acidocerini species, third instar, ventral view. A – Agraphydrus narusei (Satô, 1960); B – Enochrus umbratus Sharp, 1884; C – Helochares nipponicus Hebauer, 1995.

Fig. 45. Mesothoracic legs of Acidocerini species, third instar, anterior view.A – Agraphydrus narusei (Satô, 1960); B – Enochrus umbratus Sharp, 1884; C – Enochrus japonicus (Sharp, 1873); D – Helochares nipponicus Hebauer, 1995.