(Figs 2A–B; 4I–L; 5G–I, S–U; 6C; 7C; 10; 12; Table 1)
Pentatoma bifida Westwood, 1837 in Hope, 1837: 43 NEW SYNONYMY (removed from the synonymy with M. reticulare).
Type specimen (Fig. 10): Pentatoma bifida Westwood, 1837, holotype female, collection site unknown (OUMNH). Labels: TYPE HEM: 249 / PENTATOMA / BIFIDA WESTOOD / HOPE DEPT. OXFORD // Macropygium / reticulare / Fabr. // TYPE. / = = / WESTW. (HOPE) / C. Hemipt. 1837 / Part I, page 43 / Distant, P.Z.S., / 1900, p. 807-825.
Distribution: Bolivia, Paraguay (Fig. 12).
Material examined: BOLIVIA, Santa Cruz, Saavedra, 27♀, 12♂, 1959 (FSCA), [-17.25277777778 - 63.211466666667]; Santa Cruz, 2♂, 1960 (FSCA); 1♀, 1973 (DAR), [-17.8 -63.1666666667]. PARAGUAY, San Pedro, 1♂, 1989 (JEE).
Diagnosis. Antennae five-segmented, first and second antennomeres subequal in length; conical projection of ventral rim of pygophore bifurcate at apex; lateral angles of valvifers VIII little projected, not attaining the imaginary line connecting the mesial thrichobotria of urosternite VII.
Male. Genitalia: conical projection of ventral rim of pygophore bifurcate at apex; posterolateral angles acute, medial projection of posterolateral angles directed dorsoposteriorly, attaining the level of the dorsal limit of segment X in lateral view; lateral projection of dorsal rim thin, spine like, dorsal to the posterolateral angle, and partially covering the medial projection; segment X slightly higher than wide in posterior view, and longer than wide in ventral view (Fig. 4I–L); parameres short, apical projection short and truncate, covered by long setae; largest axis of head equals half the length of stem (Fig. 5G–I); vesica without lateral projections; ductus seminis distalis slender, middle portion twisted (Fig. 5S–U).
Female. Genitalia: Valvifers VIII longer than wide, lateral angles little projected, not covering all the basal portion of laterotergites IX, reaching the level of a line connecting the mesial thrichobotria of urosternite VII; lateral margins of valvifers VIII reaching the laterotergites VIII; laterotergites IX with mid-lateral depression (Fig. 6C). Folds of valvulae IX with few villi, conical microsculptures conspicuous; thickening of vaginal intima translucent; ring sclerites half the diameter of orificium receptaculi, this almost the width of the vaginal intima (Fig. 7C).
Comments. Macropygium bifidum is known only from Bolivia (Fig. 12), with an overlapping distribution with M. reticulare and M. spinolae. The pygophore in M bifidum is easily differentiated from M. reticulare and M. spinolae by the bifid apex of the conical projection in the ventral rim (Fig. 4I), and by the slender segment X with subparallel lateral margins (Fig. 4I, J). The conical projection and the segment X in M. graziae (Fig. 4M, N) are similar to M. bifidum, but in M. graziae the lateral projections of the dorsal rim are broad and placed apart from the posterolateral angles of the pygophore (Fig. 4O), while spine-like and close to the posterolateral angles in M. bifidum (Fig. 4K). Female genital plates in M. bifidum are similar to M. reticulare and M. spinolae, as discussed in the comments made to M. reticulare. The valvifers VIII in M. bifidum are narrower than M. spinolae, not covering the limits between the laterotergites VIII and IX (Fig. 6B, C). The valvifers VIII in M. bifidum are relatively longer than M. reticulare, surpassing posteriorly an imaginary line connecting the spiracles in laterotergtes VIII by at least twice the spiracle diameter (Fig. 6C).