Brachystethus tricolor Bolívar 1879

Brachystethustricolor Bolívar, 1879

(Figs. 8, 18, 28, 38, 48, 59)

Brachystethustricolor BOLÍVAR, 1879:138; LETHIERRY & SEVERIN, 1893:187 (cat.); KIRKALDY, 1909:152 (cat.); FROESCHNER, 1981:69 (cat.).

Typematerial. Lectotype, heredesignated, labeled: a) Baeza (Ecuador), 4/mar - 20/abr/1865, F. Martinez; b) Expedición al Pacífico (1862-1865); c) M.N.C.N., Madrid; d) Brachystethustricolor Bol.?; e) sintipo? (MNCS); paralectotypes,, both labeled: a) Martinez Baeza / 481; b) Baeza (Ecuador), 4/mar - 20/abr/1865, F. Martinez; c) Expedición al Pacífico (1862-1865); d) M.N.C.N., Madrid; e) Brachystethustricolor Bol.?; f) sintipo? (MNCS). Typelocality: Baeza, Ecuador. (“Baeza Americae Equatorialis”).

Description. Dorsal surface black, except corium and, in some specimens, part of pronotum, reddish (fig.8). Head entirely black, with conspicuous wrinkles. Mediumsized punctures moderate to sparsely distributed. Antennae black; fourth antennal segment cylindrical. Second antennal segment slightly longer than first and about 3/4 as long as third; third slightly morethan half of fourth; fifth the longest, a little less than one and a half as long as fourth. Pronotum entirely black, or, in some specimens, with about basal 2/3 reddish. Anterolateral margins entirely black or with a thin subcaloused, yellowish border. Medium-sized punctures concentrated before cicatrices. Some specimens with verycoarse punctures on basal 2/3, decreasing in size posterad. Scutellum black, sometimes slightly reddish in the middle. Coarse punctures, in variable density, decreasing in size toward apex. Remaining punctures medium-sized to fine, distributed allover surfaceof scutellum. Corium reddish, except along costal margins, with a narrow black stripe variable in length, and a little black spot, irregular-shaped, entad to apex of radial vein. Yellowishcallus nearand entad apex of radial vein, lackingin some specimens. Costal margins, in some specimens, with a thin, subcalousedyellowish border, evanescent posterad. Ventral surface of thorax black, sometimes reddish-castaneous on propleura and near coxae. Punctures concolor. Ostiolar rugae short, extending by about 1/3 of distance between inner margin of ostiolum and lateralmargin of metapleura. Metasternum, in profile, little elevated anteriorly; transversal sulcus in the middle. Legs black, coxae reddish-castaneous. Connexivum mostly black; in some specimens, a reddish stripe of variable width along inner margin. Venter red, with rounded black spots around each spiracle and one black continuous stripe along lateral margins, variable in width, occupying one fourth to half the distance between spiracles and lateral margin of abdomen. Some specimens present, on sternites III to VI, entad to spiracles, elliptical black spots, variable in size. Anterior and posterior margins of sternites occasionally with blackish stripes. Punctures sparse, fine and concolor with venter, more concentrated over black spots entad to spiracles. Spiracles black.

Male genitalia. Pygophore quadrangular, equally wide at apex and base. Lobes of dorsal rim conspicuous, strongly projected posterad, rounded at apex. Genital cup processes little visibledorsally (figs. 18, 28). Parameres with acute apex, turned toward tenth segment (fig. 48). Ventral rim not so openly V-like as in other speciesof the genus (fig. 38).

Measurements (n=4). Headlength 1.80 (1.72-1.87) ± 0.06, width 2.71 (2.61-2.77) ± 0.07; interoculardistance 1.46 (1.37-1.56) ± 0.08; anteocularlength 0.60 (0.56-0.62) ± 0.03; lengthof antennalsegments: I - 0.97 (0.94-1.01) ± 0.03; II - 1.12 (1.05-1.20) ± 0.06; III - 1.44 (1.25-1.56) ± 0.14; IV - 2.53 (2.50-2.56) ± 0.03; V - 3.44 (3.39-3.48) ± 0.06; pronotal length 3.86 (3.34-4.09) ± 0.35, width 9.14 (8.52-9.69) ± 0.50; scutellarlength 5.95 (5.52-6.35) ± 0.41, width 5.72 (5.36-6.01) ± 0.28; coriumlength 8.64 (8.52-8.77) ± 0.18; abdominalwidth 10.23 (9.69-10.69) ± 0.46; totallength 14.15 (13.53-14.86) ± 0.55.

Female genitalia. Posterior borders of gonocoxites 8 in an obtuse angle near limit between laterotergites 9 and gonocoxites 9. Sutural borders of gonocoxites 8 parallel and contiguous, except at apex (fig. 59).

Measurements (n=1). Headlength 1.87, width 2.89; interoculardistance 1.56; anteocularlength 0.62; lengthof antennalsegments: I - 1.17; II - 1.29; III - 1.40; IV - 2.77; V - 3.59; pronotallength 3.84, width 9.69; scutellarlength 6.24, width 6.00; coriumlength, not measured; abdominalwidth 11.19; totallength 15.20.

Material examined. ECUADOR,, “71”, E. de Ville col., “Coll. R.I. Sc. N.B.” (DARC).

PERU, Ucayali: Aguaytía (295m, low jungle),, 13.IX.1946, F. Woytkowski (USNM); Huánuco: Chinchao (25 Km below Carpish, 2500m),, 13.IX.1946, F. Woitkowski (AMNH).

Distribution. Ecuador, Peru (Ucayali, Huánuco).

Comments. Brachystethus tricolor is the sister species of B. vexillum, with which shares two synapomorphies and one homoplasy, respectively: venter predominantly red, metasternal carina transversely sulcated and ostiolar rugae short (BARCELLOS & GRAZIA, 2003). These characters also separate both species from theremaining species of the genus. Brachystethus tricolor can be distinguished from B. vexillum by dorsal color with red spots, and quadrangular shape of pygophore.