Megatracheloides, Lucas, 1920

Wanat, Marek, 2008, The Apionidae (Coleoptera: Curculionoidea) of New Caledonia. Genus Megatracheloides, Mémoires du Muséum national d'Histoire naturelle 197, pp. 297-322 : 300-305

Genus MEGATRACHELOIDES Lucas

Megatracheloides Lucas, 1920: 398 (replacement name for Megatrachelus Faust, 1889 , nec Abeille de Perrin, 1845).

Type species: Megatrachelus chloris Faust, 1889 . DIAGNOSIS. — Large apionids, usually well over 4.0 mm long (without rostrum), easily distinguished from members of other New Caledonian genera by inflated, pyriform elytra having markedly distinctly convex at least the inner intervals, and deeply impressed striae with always evident specific apical arrangement (isolated stria 9 reduced, 2 joining 7, and 8 free) shared only with the closely related genera Rhadinocyba and Himantapion . Unlike these two genera, in Megatracheloides the characters listed above are uniquely combined with profemur always longer and thicker than meso- and metafemur and armed with a tooth or spine, divaricate tarsal claws bearing long and thin, acute teeth, and the wing having almost complete anal cell.

DESCRIPTION. — Length 3.5-8.2 mm. Rostrum stout although much thinner than the swollen profemur, at least 1.5 x longer than pronotum, asetose; underside of prorostrum devoid of sulci, polished, at most confusedly punctured; scrobes long and distinctly edged, extended to underside of head; labral incisions and setae absent. Head elongate, subconical, asetose; frons nearly as wide as rostrum base, depressed; temples impunctate, with obsolescent wrinkles; vertex not declining posteriad. Antennae slender; scape thin, longer than mesorostrum breadth, as long as at least 4 (♂) or 5 (♀) basal fs combined; fs1 and fs2 subequal in length; club compact, markedly elongate. Pronotum globose at sides (Fig. 11), transverse, widest at apical third; subapical constriction very short and abrupt, with deep lateral fovea extended as a depression across pronotal disc; basal rim and subbasal line distinct; posterior lateral groove deep, with evident “spur” at upper end (Fig. 29); prosternum about 5 x shorter than hypomeron; posterior rim of procoxal cavities high. Scutellum isodiametric to slightly elongate. Elytra pyriform, 1.1-1.5 x longer than broad, markedly rounded and highly convex, posteriorly strongly declining, without separate caudal part; basal rim distinct; striae complete, broad and deeply impressed throughout, punctured, without sharp edges; at base stria 1 confluent with elytral rim, rarely reaching the straight stria 2; apical arrangement of striae 1 + (9 + 10), 2 + 7, 3 + 4, 5 + 6, 8 (Fig. 16); intervals on elytral disc markedly convex, roughly microsculptured and irregularly, transversely grooved; sensory setae numerous through all odd intervals. Wings fully developed and functional; radial window long and narrow; 2A with a1-a2 spur in distal third and long a2-a3, forming almost complete anal cell with long 3A. Metaventrite weakly longer than diameter of mesocoxae. Abdomen sub-isodiametric. Legs long and robust; pro- and mesocoxae very large and prominent; femora without pseudotrochanter; profemur being the longest and the thickest, bearing a tooth or spine in both sexes; ts1 flattened, ts2 markedly emarginate, strongly narrowed towards the nearly pointed base; claws large, divaricate, with long and narrow, acute teeth (Fig. 26).

Male: profemoral tooth usually larger and modified; protibial apices slightly turned or expanded inwards. Abdominal V5 truncate or emarginate, with half-erect pilosity. Pygidium (T8) largely exposed and devoid of transverse ridge or sulcus (the exposed aspidapionine type), with raised marginal rim. S8 emarginate, without carinae. Tegmen articulated; parameroid plate deeply divided; apical lobes double; suprafenestral sclerites either transverse and truncate or with long outer extensions; macrochaetae few, minute; fenestrae large, well margined; postfenestral plate very short, divided; prostegium completely divided, well sclerotized, with deep lateral incisions and very long paired projections. Aedeagus: endophallus largely projecting beyond pedon + tectum in repose, unilobed, without sclerites; flagellum short, filiform, with thin ejaculatory duct entering terminally (Figs 78-80).

Female: rostrum and antennal scape evidently longer. Abdominal V5 rounded, apically notched and/or grooved. T7 largely sclerotized. Terminalia: styli inserted apically on coxitae, narrow and elongate; coxitae evenly sclerotized, with flattened and rounded apices, weakly divergent; S8 with minute basal plate (Fig. 87); T8 with complete marginal sclerotisation (Fig. 88); bursa copulatrix long, narrowing distad (Figs 97-100), corrugate, receiving spermathecal duct ventrally in about mid-length; spermatheca with corpus not separated from cornu, apically narrowing and strongly upcurved, with the openings of duct and gland very close to each other; spermathecal duct long, progressively thickening towards bursa (Fig. 97).

BIOLOGY. — All the species of Megatracheloides are confined to various species of Hibbertia (Dilleniaceae) ; adult beetles were observed feeding on flowers and leaves (Figs 105-110). Developmental data remained unknown for a long

FIGS 1-13. 1, Megatracheloides chloris , male body, lateral view. 2, M. chloris , female head, lateral view. 3, M. bidentipes , male head, lateral view. 4, M. bidentipes , female head, lateral view. 5, M. chloris , median part of elytra, dorsal view. 6, M. bidentipes , median part of elytra, dorsal view. 7, M. chloris , female head and pronotum, dorsal view. 8, M. bidentipes , female head, dorsal view. 9, M. bidentipes , male head, dorsal view. 10, M. blaffarti , head and pronotum, male, dorsal view. 11, M. blaffarti , head, female, dorsal view. 12, M. blaffarti , head, female, lateral view. 13, M. blaffarti , pronotum and elytra, female, dorsal view. Scale bars: 2.0 mm (Fig. 1), 1.0 mm (remaining Figs).

time, and immature stages were first collected (still undescribed) by the author in 2007. Females lay eggs singly to the fully developed flower buds (Fig. 110), the larva feeds on soft petals and generative organs inside the bud, which usually falls down on the ground soon after infection. Pupation takes place in the bud and teneral adult beetles appear on leaves in December-March, following extended flowering season of the host plants.

DISTRIBUTION. — New Caledonia (only the Grande Terre).

KEY TO SPECIES OF MEGATRACHELOIDES

1. Elytral intervals 2-5 asymmetrically convex, each highest along its outer side (Figs 45, 49). Male profemoral tooth simple, thin (Figs 46, 47). Female metafemoral tooth small, pointed .................... 2 — Elytral intervals regularly convex, each highest in middle, at most with flattened, elongate tubercles. Male profemoral tooth stout, bifid or with swollen base. Female metafemoral tooth obsolescent or absent ................................................................................................................................................................. 3

2. Sixth elytral interval in mid-length with conical prominescence or pointed angulation (Figs 45, 50). Profemoral tooth thin, elongate (Fig. 46). Male: tegminal plate with outer apical lobes small and narrow, only slightly longer than fenestrae and well separated from inner lobes (Fig. 85); aedeagus progressively narrowing from base to apex (Fig. 60) .................................................... M. cornutus n. sp. — Sixth elytral interval in mid-length with obtuse angulation (Figs 49, 51). Profemoral tooth short, not higher than broad at base (Fig. 47). Male: tegminal plate with outer apical lobes large, as broad as parameroid lobes and as long as the remainder of the plate (Fig. 86); aedeagus abruptly constricted in mid-length to form well separated parallel-sided apical part (Fig. 61) .................. M. jourdani n. sp.

3. Male: profemoral tooth bifid, with additional tooth at least half as long as the main one (Fig. 22); abdominal V5 distinctly emarginate, with very shallow, broad median impression (Fig. 33); tegminal parameroid lobes strongly expanded at outer side, each much longer than broad and bearing a small membranous lobe on inner side (Fig. 69). Female: rostrum more than 2× longer than pronotum and more than 6× longer than broad at antennal insertion (Fig. 4); abdominal V5 with apical sulcus margined with a pair of pointed teeth when viewed from behind (Fig. 37) ................

............................................................................................................................................. M. bidentipes n. sp. — Male: profemoral tooth single, with asymmetrically swollen base, at most with rudimentary additional tooth (Figs 19, 30); abdominal V5 subtruncate, with a narrow, triangular impression (Fig. 32); tegminal parameroid lobes truncate, distinctly transverse, each bearing a pair of membranous lobes (Fig. 68). Female: rostrum less than 2× longer than pronotum and less than 6× longer than broad at antennal insertion; apical margin of abdominal V5 with a shallow median groove, widely open when viewed from behind (Figs 36, 38, 40) ............................................................................................................. 4

4. Elytra brightly metallic blue or green, evidently pyriform; intervals 4-6 usually with low, ill-defined, elongate tubercles in about mid-length (Fig. 5). Male: aedeagus with tapering apex (Fig. 56). Female: abdominal ventrite 5 semicircular, with distinct marginal ridge and broad median fovea (Fig. 36) ....

..................................................................................................................................................... M. chloris (Faust) — Elytra dull black or with very slight bluish reflex, more regularly oval in outline; intervals evenly convex, with no trace of prominescences in mid-length (Figs 13, 16). Male: aedeagus with narrow parallel-sided apex. Female: abdominal ventrite either with lower ridges and narrower fovea, or with distinct lobes separated by deep and broad fossa ........................................................................................ 5

FIGS 14-27. 14, Megatracheloides millei , male head,lateral view. 15, M. millei , female head,lateral view. 16, M. bidentipes , elytron,latero-posterior view. 17, M. bidentipes , pronotum, dorsal view. 18, M. millei , pronotum, dorsal view. 19, M. chloris , male profemur. 20, M. millei , female head, dorsal view. 21, M. millei , male head, dorsal view. 22, M. bidentipes , male profemur. 23, M. millei , female elytra, dorsal view. 24, M. millei , female elytra, front view. 25, M. millei , male profemur and protibia. 26, M. bidentipes , tarsal claws. 27, M. bidentipes , protarsus. Scale bars: 1 mm (Figs 14-16, 20-24), 0.5 mm (Figs 17-19, 25, 27), 0.25 mm (Fig. 24).

5. Body length <6.0 mm. Elytra with weak bluish reflex. Male: profemoral spine with obsolescent basal swelling; apex of protibia curved inwards, not expanded (Fig. 25); aedeagus in profile sinuous subapically, apex with a downward expansion (Fig. 65); outer apical lobes of tegminal plate distinctly longer than inner lobes (Fig. 70). Female: abdominal ventrite 5 with large apical lobes separated by deep fossa (Figs 38, 39); spermatheca less curved between corpus and cornu (Fig. 103). On Hibbertia wagapii Gilg. ................................................................................................................. M. millei n. sp. — Body length> 7.0 mm. Elytra dull black. Male: profemoral spine with evident basal swelling; apex of protibia expanded inwards (Fig. 30); aedeagus in profile straight subapically, its apex raised upwards (Fig. 64); outer apical lobes of tegminal plate subequal in length to inner lobes. Female: abdominal ventrite 5 semicircular in outline, with low apical rim divided by narrow fovea (Fig. 40); spermatheca markedly curved between corpus and cornu (Fig. 101). On Hibbertia comptonii Baker .......................................................................................................................................... M. blaffarti n. sp.