Anagonia rufifacies (Macquart, 1847)

Colless, Donald H., 2012, The Froggattimyia-Anagonia Genus Group (Diptera: Tachinidae), Records of the Australian Museum 64 (3), pp. 167-211 : 186-188

Anagonia rufifacies (Macquart)

Figs 23–26, 82

Masicera rufifacies Macquart, 1847: 87.

Masicera rubrifrons Macquart, 1847: 85.

Anagonia spylosioides Brauer & Bergenstamm, 1891: 349.

Type. Holotype male in BMNH, Tasmania.

Synonymy by Crosskey, 1966:99.

There is considerable variability in the “hairiness” and colour of males, to such an extent as to throw doubt on the

conspecificity of the extreme variants. However, I see no need to invoke more than a single species (see “Discussion” below). I describe below, first, the dark, “hairy” form, which is very common and to which the type specimen belongs. It is found typically at higher elevations and in cooler climates. I then describe the differences in the paler “non-hairy” form, found mainly in less elevated, drier and warmer climates. I must stress, though, that although many specimens conform to one or the other description, intermediates are common, failing in from one to a few attributes.

Male— dark form. Ground colour of integument largely dark brown to black, except on scutellum, tibiae, anteriorly on head, and laterally on abdomen. Bristles and hairs all dark, except for soft white hairs on occipital and postgular regions of head.

Head. Width 2.5–3.3, mean 3.0 mm, about 5 times as wide as frons, ratio Frw/Hdw, mean 0.19; ratio Gnw/Eyh 0.3–0.4, mean 0.35; Ivb/Vb-E 0.9–1.4, mean 1.3. Eye conspicuously haired. Fronto-orbital plate dark in ground colour; parafacial similar but often paler along anterior margins, sometimes completely pale; genae and face mid brown; all with thin

silvery or pale golden frosting; postorbital stripe silvery in lateral view, sometimes apparently discontinued at about mid height of eye. Scape and pedicel brown, first flagellomere black, with brown or dark brown arista; aristomeres 2 and 3 with light silvery frosting. Reclinate upper frontal hairs rather erect, their tips often crossing only slightly or not at all; the more dorsal members (not to be confused with the reclinate upper orbitals) often very fine, scarcely or not at all differentiated from adjacent soft hairs. One or 2 pairs of reclinate upper orbital bristles in line with reclinate upper frontal bristles; outer vertical bristles not differentiated; inner vertical bristles slightly reclinate. Soft hairs of frontoorbital plate and vertex profuse, relatively long, and many with sharply curved tips. Ocellar bristles almost always undifferentiated; postocellar bristles 2, erect but with fine proclinate tips. Upper occiput with hairs in the postocular row relatively long and of roughly uniform length (although becoming shorter laterally), behind them 1–3 rows of short dark hairs. Parafacial completely haired, the hairs profuse, dark, and relatively long.

Thorax. Mesonotal pollen sometimes with purplish tinge; presutural median dark vitta present, usually not reaching suture. Fine hairs profuse and relatively long; notopleural area more or less completely setulose; presutural intra-alar bristle sometimes rather fine, but almost always present; postsutural intra-alar bristles normal; intrapostalar bristle

not developed. Scutellum relatively broad at base, Sbs/Ssa 2.7–3.6, mean 3.05, usually brown, with diffusely darkened strip across base and small paler area at apex; apical setae usually diverging or parallel, almost always upcurved or, if straight, directed strongly upwards, fine (at longest, still conspicuously shorter and finer than preapicals). Pleuron with ground colour and all bristles and hairs (including proepisternal hairs) dark brown to black.

Legs. Dark brown, except for tibiae, which are almost invariably at least a little paler than femora, usually clearly so (suitable lighting angle may be required). Foretibia with poorly differentiated row of some 3–6 small ad spines on basal half; preapical ad bristle quite variable, from

conspicuously shorter and finer than d bristle up to almost as stout and 0.8 times as long. Midtibia with 1–2 smaller ad bristles basad of stout subcentral one. Hindtibia with ad comb bristles close set, relatively long, fine, and regular, except for 2–4 longer ones (1 subcentral and 1 preapical); the subcentral pd bristle (pd1) placed at apex of a row comprising 1 shorter hair and several much shorter ones; pd1 itself shorter than distance from its base to that of preapical d bristle, ratio Pd1/ Sdd 0.6–0.9, mean 0.80.

Wing. Membrane grey, sometimes very lightly infuscated near the wing base, veins brown. Tegula dark brown to black; basicosta mid brown to dark brown, the two concolorous or (sometimes) the former rather darker than the latter. Calypters usually brownish, occasionally paler; hairs at junction of calypters usually brown, sometimes golden.

Abdomen. Ground colour (sometimes obscurely) paler laterally on a posterior strip of syntergite 1+2, all of tergite 3, and anterior ¼– 3 ⁄ 4 of tergite 4; pale area on tergite 3 extending about half way to midline in dorsal view, that on tergite 4 somewhat smaller, both rather more extensive in ventral view. Viewed posteriorly at a low angle, tergites strongly silver-grey pollinose, except for incomplete dark median vittae on tergites 3 and 4, and sometimes tergite 5, large submedian triangles on tergite 3, and dark spots around bases of major bristles and hairs. tergite 3 with pair of well-developed submedian marginal bristles; a poorly differentiated pair often present on syntergite 1+2 also.

Terminalia (Figs 23–26). Principal features are: (a) syntergosternite 6–8 in lateral view longest in the dorsoventral dimension; (b) surstylus relatively broad, sometimes more or less parallel-sided, but usually broadest on central third, then bluntly tapering; also, from about as long as cerci to (usually) a little shorter and strongly setulose on external surface; (c) cerci more or less approximated in posterior view, in lateral view diagonally truncate apically, posteroapical margin usually slightly concave, apex therefore characteristically sharp-pointed; epiphallus moderate, smaller than postgonite.

Male— pale form. Essentially resembling the dark form, but with many (rarely all) of the following attributes.

Head. Gena, face, and parafacial all with pale brown ground colour, sometimes extending on to anterior parts of fronto orbits. Reclinate upper frontal bristles more strongly inclinate and cruciate, clearly differentiated right up to reclinate fronto orbitals; associated soft hairs shorter and less profuse. Second postocular row sometimes with a few pale setae, especially towards centre of head (correlates with hairiness of eye). Parafacial setulae not noticeably long or profuse. Eye moderately to sparsely haired.

Thorax. Calypters usually pale, hairs at their junction pale also.

Abdomen. Integument of tergite 3 dark on up to central ⅓; that on tergite 4 sometimes a little wider.

Female. Identified here by co-occurrence with males and general resemblance. Unlike the male, there is no obvious differentiation into pale- and dark forms. All are generally similar to the pale form male, except in the following:

Head. Head width 2.2–3.7 mm; frons wider, 0.25–0.30 of head width. Short hairs of dorsum of head and thorax shorter, less conspicuous.

Thorax. Scutum with stout grey dusting (or pale golden in Tasmanian specimens), presutural median vitta faint or (usually) absent. Pleuron with fine hairs all pale except on anepisternum and upper anepimeron; rarely (in large specimens) dark hairs intruding on to upper katepisternum and anterior anepimeron.

Legs. Foretibia with spines in ad row stouter, conspicuous. Midtibia with subcentral ad spine long, about as long as distance between its base and that of the apical spine. Hindtibia with ad row coarser, the spines less uniform in length. Wing with basicosta usually pale brown.

Abdomen. Tergites uniformly dark, without lateral pale areas. Sternite 1 with pale brown hairs.

Terminalia ( Fig. 82 ). Segment 6 much shorter than deep; Tergite and sternite 6 well developed, the former with spiracles included within its margin; posterior margin of sternite 6 sometimes with a very slight median process bearing a few setulae. Tergite 7 large, extending to about midline in lateral view, in dorsal view its posterior margin deeply emarginate; sternite 7 with a distinctive “scoop-like” shape, its ventral margin sinuous, posteriorly forming a tapering gutter that ends in a more or less completely closed pore. Relics of tergite 8, and sternites 8 and10 distinct.

Distribution. Widespread, in all states and climates except the wet tropics.

Biology. All reared specimens came from larvae of paropsine chrysomelid beetles: Chrysophtharta bimaculata (Olivier), C. variicollis (Chapuis), C. agricola (Chapuis), C. amoena (Clark), C.?decolorata (Chapuis), Paropsis porosa Erichson, and Peltoschema rubiginosa (Chapuis). The large bulk of rearings, however, are from Tasmania, where the species is a major parasite of C. bimaculata, itself a major pest of eucalypt forests. On the mainland, and especially in more arid areas, the principal hosts are unknown.

Notes. The variability of the males can render identifications of paler specimens somewhat insecure if based on external morphology alone. The terminalia are, however, immediately recognizable—in particular, the sharply oblique truncation of the cerci in lateral view. The shape of the female sternite 7 seems prima facie diagnostic, but females of several closely related species remain as yet unrecognized. Indeed, it cannot be excluded that the females described above, although associated with males in various ways, might include specimens of A. loripes and A. conformis.

Figures

Figs 82–86. Anagonia female terminalia, lateral views. (82) Anagonia rufifacies, (83) A. tillyardi, (84) A. lasiophthalma, (85) A. dayi sp. nov., and (86) A. commoni sp. nov.