Euschistus (Euschistus) heros (Fabricius, 1798), Euschistus (Lycipta) riograndensis Weiler & Grazia, 2011, and Euschistus (Mitripus) paranticus Grazia, 1987

(Figs. 2, 3, 31–42; Tab. 2)

Eggs barrel-shaped; color prior to embryonic development light green (in E. heros) or white (in E. riograndensis and E. paranticus) (Figs. 2, 3); operculum round, with variable convexity, usually slightly convex (Figs. 2, 3), but conspicuously flatter in E. heros; chorion translucent and spinose. The eclosion line is not evident under SM; the AMPs are circularly arranged in a row around the anterior pole, white, moderately long and filiform (Figs. 2, 3).

The chorion surface of all species of Euschistus Dallas studied here is densely spinose under SEM. The interconnected spines form polygonal markings that are mostly triangular at the lateral wall (Figs. 31, 39). The spines display different sizes, being usually thicker and longer at the triangle vertices (Figs. 33, 37, 38). This pattern may be obscured by traces of adhesive material gluing adjacent eggs (Fig. 39). The operculum is similarly sculptured, with interconnected spines forming triangles (Figs. 32, 36, 40). The spines are shorter at the center of the operculum, and polygonal markings are sometimes obliterated (Fig. 36). The spines display different sizes and are interconnected by a short membrane at the periphery of the operculum (Figs. 34, 41). The eclosion line is not evident. The AMPs are tubular in E. riograndensis (Fig. 38) and slightly clubbed in the two other species (Figs. 33, 34, 41). Their openings are circular and apical, and there are fine connector sheets among adjacent AMPs in E. heros (Fig. 34). The surface of the AMPs is spongy under higher magnification (Figs. 35, 42).