Amenia dubitalis Malloch, 1927

Colless, D. H., 1998, Morphometrics in the genus Amenia and revisionary notes on the Australian Ameniinae (Diptera: Calliphoridae), with the description of eight new species, Records of the Australian Museum 50 (1), pp. 85-123 : 110

Amenia dubitalis Malloch rev.stat.

Amenia dubitalis Malloch, 1927: 343 .

Amenia imperialis dubitalis Crosskey, 1965: 111 .

Differs from A. imperialis in the attributes given in the key. The narrow frons of the male is particularly striking and in both sexes the difference in facial pollinosity, while seemingly rather trivial, is conspicuous under the stated conditions of lighting. For both sexes the M-bend index is 0.7-1.2; the antennal segment ratio is 2.2-3.1 for males and 2.4-2.6 for females.

In the one male dissected the surstylus had a subbasal group of 3-4 bristles on the anterior surface, as opposed to a single bristle for other members of the group.

I have one new rearing record: a male (24 km SE of Bonshaw, NSW, 31 March 1990, PH. Colman; AM) from Strangesta sp. ( Rhytididae ).

Distribution. Eastern Australia, from about Ingham in the north to southeastern Victoria; restricted almost entirely to the coast and adjacent ranges ( Fig. 3 ) A close examination of records shows a marked deficiency from the more inland localities of southeastern Queensland (Fig. 4), as compared with A. imperialis ( Fig. 6 ). The area is well-collected and the difference is clearly significant, presumably reflecting some difference in host snails.

Notes. The difference between females from the border area between Queensland and New South Wales and further south, which almost invariably have submedian marginal bristles on abdominal T3 , and those from further north, which almost invariably lack them, could well be used to establish two separate subspecies. However, I see no point in taking this step. The change is quite abrupt, at about the latitude of Brisbane: between there and the 25th. parallel, six out of 13 specimens had such bristles, and furthernorth, only one out of 21 (and that very small). Per contra, only two out of 47 specimens from more southern localities (Sydney and Narrabri) lacked such bristles, two had only a single bristle, and two had three bristles .

Figures

Figure 3. Distribution of Amenia dubitalis and Amenia crinita (overlapping records omitted). Filled circles =A. dubitalis; filled squares = A. crinita.

Figure 6. Details of recorded distribution of Amenia imperialis in southeastern Queensland and northeastern New South Wales (compare with Fig. 4).