Melobasis formosa, Carter, 1923

Levey, Brian, 2012, 3464, Zootaxa 3464, pp. 1-107 : 38-39

M. formosa Carter

(Figs. 102, 103, 165, 214, 215)

Melobasis formosa Carter 1923:99 ; 1929:284; Obenberger 1930:430; Bellamy 2002:151; 2008:1321. Type locality: Western Australia, Southern Cross.

Type specimens examined. Lectotype ♂, (here designated), ( SAMA), Southern Cross W.A. H.W. Brown / Melobasis formosa Carter Id. by H.J. Carter / LECTOTYPE Melobasis formosa Carter B. Levey det. Paralectotype ♀ ( SAMA), mounted on same card as Lectotype.

Other specimens examined. Western Australia: Cue; Cunderdin; Dedari; Geraldton; Lake Grace; Southern Cross; Spencers Brook; Swan River; Marloo Stn., Wurarga; South Australia: Quorn; Queensland: Mackay (undoubtedly wrongly labelled). Specimens examined from ANIC, AMSA, BMNH, IRSNB, KEC, MVMA, NMWC, SAMA, UQA, WADA, WAMA, ZMHB.

I have examined a series of five specimens (3♂, 2♂) from 18 km S. of Cobar, N.S.W., 9 Jan. 2005, on fine leaf Acacia collected by Mark Hanlon that differ slightly in colour and markings from other M. formosa I have examined, and are from well outside the known distribution of the species. However, the aedeagus, the punctation and the shape of the apical sternite fall within the range of variation seen in M. formosa from W. Australia. These specimens may be representatives of a taxon deserving subspecific status, however, without further material from other localities, I do not think it is possible to decide if they represent a well defined subspecies or are just part of clinal variation in M. formosa .

Diagnosis. General diagnosis: length 8.8–11.2 mm.; head and pronotum usually brownish-, greenish- or blackish-bronze, rarely greenish-blue; elytra usually deep purple or deep-reddish purple, rarely brownish-copper, with the following coppery, golden-green or green markings: a sutural vitta in the basal quarter (sometimes absent); a slightly shorter humeral vitta (sometimes reduced or absent), which may extend narrowly along the basal margin to the epipleura; a sinuate transverse fascia, which is sometimes reduced to a roughly ovate macula; a roughly obovate pre-apical macula (sometimes reduced or absent); underside brownish- or greenish-bronze, sometimes with reddish-purple or coppery reflections; lateral parts of underside moderately densely clothed with fairly long silvery pubescence.

Head: upper third of vertex moderately densely punctured with small round punctures; remainder of head very densely punctured with ovate punctures which largely coalesce to form short linear series orientated dorsoventrally on the lower half of the vertex and the frontoclypeus; moderately densely clothed with moderately long silvery pubescence; unpunctured areas shiny or very weakly microretriculate; clypeal excision fairly deep, Ushaped, with an unpunctured shiny to weakly microreticulate border which is often confined to the middle of the excision; clypeal peaks slightly acutely angled; vertex flat to very slightly convex, about half to slightly more than half width of head across eyes when viewed from above; eyes moderately convex.

Antenna: serrate from segment 4–10, the segments becoming progressively smaller and slightly less elongate, the expanded part of each segment more or less quadrate in ♂, in ♀ segment 4, 5 and sometimes 6 more or less triangular, the rest more or less quadrate.

Pronotum: 1.49–1.65 times as wide at base as long in midline; anterior margin weakly bisinuate, with a slightly developed broad often strongly truncated median lobe; posterior margin bisinuate; widest behind, at or in front of mid-length; lateral margins weakly rectilinearly diverging from the posterior angles to widest point, (sometimes slightly sinuate near posterior angles), thence weakly to moderately strongly curvilinearly converging to the anterior angles; as wide as or slightly narrower at base than elytra at base; lateral carina almost straight or slightly sinuate, about half to three-quarters complete; punctation sparse to moderately dense in central fifth, consisting of small round punctures, which become progressively larger and denser towards the lateral margin; with a complete or incomplete unpunctured midline; shiny without microreticulate microsculpture; moderately densely clothed with fairly long silvery pubescence in lateral half.

Scutellum: variable in shape, almost round, ovate or quadrate, about one-fourteenth to one-seventeenth width of elytra at base; often with a puncture or dimple.

Elytra: 2.05–2.52 times as long as wide at the base; basal margin moderately strongly bisinuate to biarcuate; parallel sided or very slightly widening from base over the humeral callosities, thence almost parallel sided to the mid-length, before narrowing to the broadly rounded apices; lateral margins from just beyond mid-length and apices with coarse acute serrations, those at the apices being slightly smaller; sutural margin slightly raised in apical half; rather uniformly punctured but with traces of one, two or rarely three costate intervals in the inner twothirds; internal of the first costate interval, sparsely to moderately densely punctured with very small round punctures; external to the first costate interval the punctures become larger and dense, to very dense near the lateral margin, where they become ovate and form short transverse series; moderately strongly microreticulate.

Proepisternum: very densely punctured with moderately large, shallow, lunate punctures, partly obscured by dense long silvery pubescence.

Prosternum: with a narrow bead at the anterior margin, the anterior margin at almost the same level as the area behind; prosternal process moderately strongly widening distally, sparsely punctured with small punctures, with a few slightly larger punctures near the lateral margin; glabrous.

Mesoepisternum: densely punctured, with moderately large, shallow, semi lunate punctures; partly obscured by long silvery pubescence.

Apical sternite: with the lunate punctures coalescent, their rims forming ridges more or less parallel to the lateral margin over most of the surface, but turned in towards the midline distally; in ♂ excision not very deep, much wider than deep, distal margin of the flange straight, the spines moderately developed, slightly shorter or as long as the depth of the flange ( Fig. 214); in ♀ excision and spines absent the sternite truncate in front of the flange ( Fig. 215).

Tarsal claws: slightly widened at base, but without a basal tooth.

Aedeagus ( Fig. 165).

Ovipositor: not examined.

Comments. This species is very variable. Specimens without or with much reduced elytral markings are likely to be confused with M. marlooensis Carter , however the aedaegus of M. marlooensis is much more elongate

Bionomics. Adults collected November–March on Acacia spp. Adult cut out of Jam Tree [ Acacia sp. (Fabaceae) ].