Chorosoma schillingi (Schilling, 1829)

Vilímová, Jitka & Rohanová, Markéta, 2010, The external morphology of eggs of three Rhopalidae species (Hemiptera: Heteroptera) with a review of the eggs of this family, Acta Entomologica Musei Nationalis Pragae 50 (1), pp. 75-95 : 78-79

Chorosoma schillingi (Schilling, 1829)

( Figs. 1–10 , Table 3)

Egg is oval, roughly bean-shaped. Dorsal side is convex, differing from all other species studied, with attachment stalk situated medially, in longitudinal axis almost centrally, only slightly closer to posterior egg pole than to anterior pole. Lateral sides are only slightly sunken/concave longitudinally, each slanting toward ventral side. Ventral side is narrower than dorsal, merging gradually into lateral sides, without any conspicuous structures, as e.g. longitudinal ribs in Rhopalus maculatus .

In hatching, the larva forces off the pseudoperculum at anterior egg pole. Pseudoperculum is rounded, almost circular, flattened and distinctly separated by paler ring with slightly indicated ridge of different structure from surrounding chorion. Convex chorionic elevations in shape of elongated rhomboids form structure of this ridge.

Chorion is dull, with tetragonal, approximately rhomboidal convex elevations emarginated by low ridges, and with small convex central plate in each tetragon. Structure of pseudoperculum is slightly different from that of surrounding chorion; ridges demarcating elevations are less distinct.

Two micropylar processes are in longitudinal egg axis, one is on pseudoperculum close to the anterior pole of egg, the other on dorsal side close to pseudoperculum and anterior egg pole. Micropyle is distinct, larger than in Rhopalini , protruding from egg outline. It has a more complicated, S shape in lateral view, with short stem and broaden apex with single opening directed roughly anteriad.

Attachment stalk is developed as distinct chorionic structure roughly in center of dorsal egg side. It is about the same size as micropyle, cylindrical with slightly broadened apex, and surface smooth.

Egg is brown after oviposition, darkening to brown to blackish.

Measurements (in mm): length 1.23 (1.14–1.33), width 0.56 (0.51–0.60).

Figures

Figs. 1–8. Eggs of Chorosoma schillingi (Schilling, 1829). 1 – whole egg, ventral view; 2 – whole egg, lateral view; 3 – anterior pole of egg, lateral view; 4 – anterior pole of egg, ventral view; 5 – empty egg with separated pseudoperculum, ventral view; 6 – detail of chorion surface pattern, pseudoperculum; 7 – detail of chorion surface pattern, egg body; 8 – detail of adhesive stalk on dorsal side, lateral view. Scale = 100 μm for Figs. 1–5; 10 μm for Figs. 6–8. Letterings: c – cap; m1, m2 – micropylar processes; p – pseudoperculum; r – ridge separating pseudoperculum from surrounding chorion; s – attachment stalk.

Figs. 9–10. Eggs of Chorosoma schillingi (Schilling, 1829). 9 – apex of micropylar process, most exposed view; 10 – cuticular cap of hatched larva attached to empty egg, with egg burster, most exposed view. Scale = 100 μm for Fig. 10; 10 μm for Fig. 9. Letterings: b – egg burster; o – opening of micropylar process.