Dilophotes Waterhouse, 1879

Kazantsev, Sergey V., 2004, Contribution to the knowledge of Macrolycini with description of Calcaeron, new genus (Coleoptera, Lycidae), Zootaxa 493, pp. 1-32 : 3-7

Dilophotes Waterhouse, 1879

Dilophotes Waterhouse, 1879: 75 .

Type species: Dilophotes exilis Waterhouse, 1878: 116 (by original designation).

Stenolycus Ohbayashi, 1956: 58.

Type species: Stenolycus ohirai Ohbayashi, 1956: 58 (by original designation).

Redescription

Head transverse, slightly narrowed behind eyes, not or hardly wider than pronotal anterior margin. Frons plane at acute angle with vertex. Gular area reduced to sub­occipital sulcus. Sub­antennal and coronal sutures complete ( Fig. 1 ). Tentorium represented by a pair of posterior arms. Labrum transverse, feebly emarginated medially, not rigidly attached to epistomal sulcus ( Fig. 1 ). Eyes spherical. Mandibles evenly rounded ( Fig. 1 ). Maxillary palpi 4­segmented, relatively stout, with ultimate palpomere flattened and dilated at apex. Mentum fully developed, submentum present; prementum undivided. Labial palpi 3­segmented, slender, ultimate palpomere flattened and dilated at apex ( Fig. 1 ). Antennal prominence moderate, antennal sockets approximate ( Fig. 1 ). Antennae 11­ segmented, long, attaining to elytral apices, strongly compressed from antennomere 3. Antennomere 2 small, transverse and more than 5 times shorter than antennomere 3. Antennal pubescence short and decumbent, with scaliform setae on antennomeres 3 to 11. Pronotum short, transverse, inconspicuously produced anteriorly, with moderately pronounced hind angles; median suture (on inner surface) complete ( Fig. 2 ). Prosternum narrow, Y­shaped ( Fig. 2 ). Mesothoracic spiracles simple, small, not extending laterally beyond coxal line. Scutellum relatively wide, more or less parallel­sided and emarginate at apex, not completely covering elytral notch. Mesepimeron narrow. Elytra slightly narrowing posteriorly, dehiscent behind middle, with three primary costae, costae 2 and 3 gradually weakening towards apex, costa 1 robust only basally, interstices with irregular reticulation; elytral pubescence uniform. Metathoracic spiracles well developed. Metathoracic wing with wedge cell present ( Fig. 3 ). Metasternal suture reaching over two thirds of metasternum; metendosternite simple, without arms, similar to that of Mesolycus ( Fig. 26 ). Procoxae elongate, approximate distally; mesocoxae transverse, separated; metacoxae divided by sutures into basal and presumably meral and trochantinal parts, with basal part similar to mesocoxa ( Figs. 4–5 ). Trochanters elongate, about twice as long as wide, but considerably shorter than femurs, connected to femurs apically; tibial spurs absent; tarsi narrow, tarsomere 4 slightly widened, tarsomeres 3 and 4 with plantar pad apically, plantar pads on tarsomeres 1 and 2 absent; all male claws bifid apically; female claws with acute tooth near base ( Fig. 6 ). Abdominal spiracles located dorsally at the edge of sternites; tergites with median longitudinal line. Ultimate female sternite without spiculum gastrale, as in Mesolycus ( Fig. 28 ). Male ultimate sternite with long, basally asymmetrical spiculum gastrale ( Fig. 7 ). Male ultimate tergite attached to penultimate one only medially; penultimate tergite deeply incised ( Fig. 8 ). Valvifers of female genitalia rigidly attached to each other by bridge ( Fig. 9 ). Aedeagus with asymmetrical median lobe, internal sac and phallobase ( Figs. 10–17 ).

Remarks

Dilophotes , the type species of which, D. exilis Waterhouse , has been studied, is characterized by the long, serrate to flabellate, antennae attaining to the elytral apices in both sexes, with scaliform setae on antennomeres 3 to 11, acute angle between the vertex and frons planes (fastigium), relatively short pronotum with complete median suture, simple mesothoracic spiracles, present wedge cell of the metathoracic wing, absent plantar pads on tarsomeres 1 and 2, presence of a median longitudinal line on tergites, rigidly attached to each other valvifers and asymmetrical median piece of the aedeagus. It is quite different from Mesolycus , where the mentioned characters are in the opposite condition. The flabellate antennomeres 3 to 10, manifest in a number of representatives of Dilophotes , are obviously of no great taxonomic value as a character, not infrequently come across in the family, including Mesolycus , as one of the most widespread homoplasies.

Figures

FIGURES 1 – 5. Details of Dilophotes depressicornis Pic. 1 — head, dorsally; 2 — prothorax, ventrally; 3 — metathoracic wing; 4 — metacoxa, dorsally; 5 — same, posteriorly. CS — coronal suture; LP — labial palpi; MR — meron; SaS — sub­antennal suture; TN — trochantin.

FIGURES 25 – 31. Details of Mesolycus shelfordi (Bourgeois). 25 — metathoracic wing; 26 — metendosternite; 27 — metacoxa, internally; 28 — female ultimate sternite; 29 — female genitalia; 30 — aedeagus, ventrally; 31 — same, laterally. MR — meron; TN — trochantin.

FIGURES 6 – 11. Details of Dilophotes depressicornis Pic. 6 — ultimate segment of female metatarsus with claws; 7 — male ultimate sternite; 8 — male ultimate and penultimate tergites; 9 — female genitalia; 10 — aedeagus, ventrally; 11 — same, laterally.