Cassida tarda Weise, 1899

Borowiec, Lech & Świętojańska, Jolanta, 2022, A monograph of the Afrotropical Cassidinae (Coleoptera: Chrysomelidae). Part 6. Revision of the tribe Cassidini 3, the genus Cassida L., Zootaxa 5171 (1), pp. 1-250 : 159-160

Cassida tarda Weise, 1899

( figs. 46 , 83–85)

Cassida tarda Weise, 1899 a: 243 ; Nummelin & Borowiec, 1991: 14.

Description. L: 4.40–4.80 mm, W: 3.55–3.80 mm, Lp: 1.45–1.55 mm, Wp: 2.85–3.05 mm, L/W: 1.23–1.26, Wp/ Lp: 1.90–2.03. Body oval (figs. 83, 84).

Disc and basal parts of explanate margin brown to black, only explanate margin laterally to head yellow (fig. 84), sometimes on disc yellowish spots and bands of diffused borders (fig. 83). Scutellum brown to black, elytral disc in dark specimens completely black in pale forms dark brown laterally, paler brown on top sometimes with yellowish brown elevations. Explanate margin yellow, in dark forms with diagonal brown to black humeral spot not extending to extreme margin of elytra and with broad brown to black posterolateral spot at least partly extending to extreme margin of elytra; in pale form humeral spot absent or very short, triangular but posterolateral spot always broad. Head brown with darker brown basal corner and sides, thorax black, abdomen black narrowly surrounded by yellow or yellow–brown. Legs yellow. Antennal segments 1–8 yellow, apical segments gradually infuscate.

Pronotum broadly elliptical, with maximum width in the middle, anterior margin regularly convex, sides broadly rounded, no basal corners. Disc more or less distinctly bordered from explanate margin, only in pale form with more or less marked lateral lobes. Entire surface of disc with more or less minutely granulate sculpture, dull, in black forms the sculpture more distinct than in pale forms. Explanate margin broad, on black parts with the same sculpture as on disc, dull, only yellow parts transparent with well visible honeycomb structure.

Base of elytra much wider than base of pronotum, humeral angles distinctly protruding anterad, angulate. Disc depressed in profile (fig. 85), with shallow postscutellar, principal and posterolateral impressions, without H–shaped elevation but with thin, elevated second interval surrounding postscutellar impressions and slightly elevated suture in postscutellar point. Punctation moderately coarse but extremely dense, only in pale form tend to forms more or less regular rows, especially in sutural area and along sides, sparse, punctures almost touching each other, intervals more or less convex. In dark form punctures tend to form transverse grooves thus surface of disc appears mostly irregularly punctate and rugose, second interval on slope form a short convex elevation often marked with yellow. Marginal row distinct, its punctures smaller than punctures in central rows. Intervals mostly not marked except parts of second and fourth and two submarginal intervals, marginal interval very narrow as wide as submarginal rows, humeral and lateral folds marked only in pale forms. Explanate margin broad, moderately declivous, in the widest part 3.5 times narrower than disc, surface with shallow, moderately coarse but dense punctation, appears irregular, only yellow parts transparent with well visible honeycomb structure.

Eyes very large, in males globular, gena obsolete. Clypeus narrow, in male slightly longer than wide in female as wide as long. Clypeal grooves fine but well marked, converging in triangle with angulate top, surface of clypeus shiny, with deep central impression, with few very small punctures. Labrum broadly emarginate to 1/5 length. Antennae moderately slim, segments 9–10 slightly longer than wide. Length ratio of antennal segments: 100:75:8 3:79:58:67:63:54:63:71:138. Segment 3 approximately 1.1 times as long as segment 2 and approximately as long as segment 4.

Prosternum moderately broad in the middle, moderately expanded apically, area between coxae deeply canaliculate, without special sculpture except row of small punctures along sides, expanded apex convex shiny, with very fine longitudinal striation and few small punctures.

Claws with small basal tooth, appears almost simple.

Distribution. Tanzania and Uganda ( fig. 46 ).

Remarks. A distinct species, well characterized by a mostly brown to black pronotal and elytral disc and dark spots at the base of pronotal explanate margin and humeral and posterolateral dark spots of elytral explanate margin (figs. 83-85). Similar pattern have only two other species: Cassida calvaria and C. rogozinskii . The first species distinctly differs in a strongly convex elytral disc, with a high postscutellar hump and some folds on the elytral slope ( figs. 75-77 ) and a smooth and shiny background of elytral and pronotal disc while in C. tarda elytral disc is depressed, without a postscutellar hump or folds on the elytral slope at most with low H–shaped folds in the postscutellar area (figs. 83-85) and a slightly granulate and dull background of elytral and pronotal disc; C. rogozinskii well differs in the absence of a posterolateral spots on elytral explanate margin ( fig. 107 ), slightly more convex elytral disc with slightly elevated postscutellar area ( fig. 108 ), fine and less dense punctation of elytra and smooth and shiny background of the elytral and pronotal discs.

Types examined. Lectotype and three paralectotypes: [ TANZANIA]: Mombo , Paul ( ZMHU).

Other specimens examined. TANZANIA: Katundu , VI 1910, 1, Holtz ( ZMHU) ; Nguru Mts. , 4.000 ft., XI 1948 ( LS) ; Panganisteppe , Mombo–Masinde, I 1906, 2, Schröder ( ZMHU, MNHW) .

UGANDA: Kibale Forest , 5 II 1984, 1, 17 I 1985, 1, 8 IV 1985, 1, M. Nummelin ( ZMUH, MNHW) .

Figures

FIGURE 46. Distribution of Cassida tarda (black circles) and Cassida thomsoni (black diamonds).

FIGURES 75–77. Cassida calvaria. FIGURES 78–79. Cassida satanas. 75–76, 78. Dorsal; 77, 79. Lateral.

FIGURES 107–108. Cassida rogozinskii. FIGURES 109–110. Cassida setosa. 107, 109. Dorsal; 108, 110. Lateral.