Morfologia externa dos cicadellinae (homoptera, cicadellidae): comparação entre versigonalia ruficauda (walker) (cicadellini) e tretogonia cribrata melichar (proconiini), com notas sobre outras espécies e análise da terminologia

Abstract

The external morphology of two cicadelline species, Versigonalia ruficauda (Walker, 1851) (Cicadellini) and Tretogonia cribrata Melichar, 1926 (Proconiini), is analyzed. The head, axillary sclerites, wing venation, female genitalia, and tegumentary processes are described. Notes on other Cicadellini - Amblyscarlidia albofasciata (Walker, 1851), Tettisama quinquemacidata (Germar, 1821), Macugonalia lencomelas (Walker, 1851), and Diedrocephala variegata (Fabricius, 1775) - and Proconiini - Ciccus adspersus (Fabricius, 1803), Homoscarta superciliaris (Jacobi, 1905), Ichthyobelus sp., and Rhaphirrhinus phosphoreus (Linnaeus, 1758) - are added. A technique for dissecting the female genitalia is presented. The facial porlion of head in V. ruficauda, T. cribrata, and remaining species has a large sclerite (frons or postfrontofrons) clearly defined by the frontogenal suture. Below the frons, and separated from it by the epistomal suture, a smaller sclerite is present (clypeus). The identification of these sclerites is based on comparisons with descriptions in the literature of a generalized Pterygota, a Psocoptera, a fossil Hemipteroidea, and other Homoptera. The conclusions about the identities of frons and clypeus corroborate the hypotheses of Hamilton (1981) on the homologies of cephalic areas in Rhynchota. The facial sclerites have modifications related with the xyleniomyzous diet. The frons is swollen, providing a larger area for attachmcnt of cibarial muscles. Other modifications increasing the area of frons are observed in the Proconiini. In C. adspersus its lateral margins are distinctly pronounced and its upper portion has a pair of lateral elevations. In Ichthyobelus sp. and R. phosphoreus the upper part of frons is greatly developed, occupying 4/5 of dorsal area of head on middle line. The vertex is limited to a small portion (1/5) of that area. The clypeus is also swollen, a fact related with the greater development of cibarium. This character is more conspicuous in the Proconiini. In this tribe the clypeus has a convex projection occupied by the cibarium, which is greatly devcloped. The pronotum and forewings in T. cribrata are covered by pits, each with a seta on external margin. These pits are similar (and maybe homologous) to struetures in the abdomen of a membracid (Goniolomus tricomiger Stål. 1869). The pronotum is smooth in V. ruficauda. However, pits similar to those of T. cribrata, although smaller. oceur near the forewing veins. A strong costal vein is present in the forewings of the 10 studied species. This vein is formed by a fusion between precosta (PC), costa anterior (CA), and costa posterior (CP). Vestiges of subcosta posterior (ScP) and media (M) occur in the forewing base. A vein formed by a fusion between anal (A) and jugal (J) veins is observed along the inner margin of clavus. In the hindwings, PC, CA, and CP are also fused. The occurrence of PC can be inferred by the presence of the wing coupling lobe. which represents its final part. Jugal anterior (JA) is fused to anal posterior (AP"). Jugal posterior (JP) occurs as a small rudiment at hindwing base. The characters of fore - and hindwings confirm the observations of Dworakowska (1988) on the Cicadellidae. The presence of PC and J corroborates Kukalová-Peck's (1983) model of the primitive pterygote venation. Comparisons between the Cicadellinae and a description of a fossil species of the order Diaphanopterodea (Kukalová-Peck 1992) revealed remarkable similarities in female genitalia. Such similarities (manifested in the positions of gonocoxites eight and nine, gonangulum, valvulae eight and nine, and lergite nine) permit a correct interpretation of the genital structurcs in the subfamily. The sclerites of the genital chamber described by Young (1977) in females of various Cicadellini are the reduced eighth abdominal sternite. Sclerotized plates in this sternite occur in A. albofasciata, T. quinquemaculata, T. cribrata, C. adspersus, and H. superciliaris. Comparisons carried out among these Cicadellinae, allied with data from the literature, indicate that the eighth sternum can provide useful characters for the subfamily taxonomy. Features of potential taxonomic interest in valvulae eight and nine include tegumentary processes (valvulae eight), shaft form, and teeth form and distribution (valvulae nine). Lists with the terms suggested for head, wings, and female genitalia are included, together with synonyms proposed by other taxonomists and morphologists