External morphology of the egg and the first and fifth instars of Cyrtocoris egeris Packauskas & Schaefer (Hemiptera: Heteroptera: Pentatomidae: Cyrto-corinae)

Abstract

Cyrtocorinae is an uncommon, small, and exclusively Neotropical group in Pentatomidae, whose immatures are poorly understood. In this paper, the egg and first and fifth instars of Cyrtocoris egeris Packauskas & Schaefer are studied with the scanning electron microscopy (SEM). Specimens were collected in Maquiné, Rio Grande do Sul, Brazil. Immatures were analyzed with light stereomicroscope and SEM. The egg’s chorion surface is predominantly smooth alternated with granulated areas, and an average of 54 clubbed aero-micropylar processes are arranged in three irregular rows. In the first and fifth instars, organization of the external dorso-abdominal scent efferent system suggests an analogy to the metathoracic external scent efferent system of the adult, because of structures similar to the evaporatorium, evaporatory channel, and auricle peritreme; the last structure is absent in the first instar. Abdominal sterna III–VII have 1+1 (first instar) and 2+2 trichobothria (fifth instar). Ultrastructural observations allowed recognition of unique characters at the egg stage and conserved features at the nymphal stage in C. egeris.