Megacerus (Megacerus) centralis ( Pic, 1913 )

Nápoles, Jesús Romero, 2018, A New Species of the Seed Beetle Genus Megacerus Fåhraeus, 1839 (Coleoptera: Bruchidae) and Redescription of Megacerus centralis (Pic), with a Key to the Mexican Species and New Host and Distribution Records, The Coleopterists Bulletin 72 (3), pp. 531-540 : 536

Megacerus (Megacerus) centralis ( Pic, 1913) ( Fig. 2a–d )

Bruchus rubiginosus Motschulsky, 1873

Bruchus centralis Pic, 1913

Redescription. Male ( Fig. 2a–d ). Length (pronotum-elytra) 3.0– 3.7 mm; width 2.5–3.5 mm; maximum thoracic depth 2.25 mm. Integument color. Body black, except profemur, protibia, mesofemur, mesotibia, mesotarsus, metafemur, metatibia, and metatarsus yellowish brown, and an anterior orange red spot on elytra extending from stria 2 to lateral border. Vestiture: Body with dense, white pubescence, except on pronotum and elytra where it is less dense; pygidium with median, glabrous, longitudinal line connected with a median glabrous transverse line to form a “T”; spiracular areas glabrous. Head: Short and broad, densely micropunctulate, frons with impunctate median carina, distance between base of eyes 0.27X as wide as eye width, ocular sinus about 0.71X width of eye, posterior margin of eye protruding from adjacent surfaces; antennae pectinate from 4 th antennomere. Prothorax: Pronotum subconical, without lateral carina; disc convex, densely foveolate, basal lobe with mesal impunctate sulcus; prosternal process narrow, triangular, acute. Meso- and metathoraces: Scutellum subsquare and sculptured; elytral striae with large punctures wider than striae; striae 1–6 reaching elytral base, 7–10 reaching humeral base; elytra with salient humeri; mesepimeron foveolate; metepisternum punctate with scattered foveolae and a dorsal curved carina; metasternum punctate with scattered foveolae. Legs: Metacoxa densely foveolate; metafemur moderately swollen, ventral carinae obsolete; internal ventral margin with blunt subapical spine; metatibia straight, enlarged, with dorsomesal, ventral, and ventrolateral carinae, lateral carina absent; mucro 0.16X as long as 1 st tarsomere. Abdomen: More or less telescoped, 5 th sternite deeply emarginated; pygidium vertical with scattered foveolae. Genitalia: Median lobe moderately long, wider at base; ventral valve triangular and deeply arcuate in lateral view; basal internal sac spinulate, with median group of about 25 spines followed by a double line of 6 spines and a basal group formed by 3 spines on each side ( Fig. 2d ); lateral lobes fused, wider than apex of median lobe, with apical setae, with median flap in ventral view. Female. Unknown.

Material Examined. Mexico: Zacazonapan, Estado de México, 25/ VI /1998; A. Luz & L. Delgado (1 ex, CEAM); Puerto Vallarta, nr. port, Jalisco, 15/VII/1987, R . H. Turnbow (2 ex RHTC, 1 ex FSCA, 2 ex CEAM) .

Host Plant. Unknown.

Distribution. Mexico (Estado de México, Jalisco).

Discussion. This species was described by Motschulsky (1873) as Bruchus rubiginosus . Because the name was preoccupied by Serratobruchidius (= Bruchus ) rubiginosus (Desbrochers, 1869) , Pic (1913) noted the homonym and designated the new name Bruchus centralis Pic. Later, Blackwelder (1946) transferred it to Megacerus . Because of Pic’ s (1913) poor description, Terán and Kingsolver (1977) published a redescription; however, the male holotype is missing some body parts, and the female is unknown. For this reason, I provide a new redescription herein. This species keys near to M. tricolor , but it can be separated easily because the pygidium exhibits a glabrous longitudinal line connected with a glabrous transverse line to form a “T”.

Figures

Fig. 2. Male Megacerus centralis. a) Dorsal habitus, b) Lateral habitus, c) Pygidium, d) Genitalia.