Metaemene niasica Pagenstecher stat. rev.

Aemene niasica Pagenstecher, 1885, Jb. nassau. Ver. Naturk., 38: 25.

Diagnosis

This species is one of a major Sundanian complex that contains at least 12 species. The forewings have series of black dots as in atrigutta, but these are surrounded by white, with brownish pink patches between the antemedial and postmedial dots, and between the latter and those on the distal and postmedial dots, and between the latter and those on the distal margins. The two postmedial black dots are between M1 and M2 (Pd1) and on the anal vein (Pd2), and the antemedial one (Ad) is also on the anal vein. In some species there may be smaller satellite dots associated with those, and there are also small ones on the costa for both zones and on the dorsum postmedially. The main marginal dots are two distal to the postmedial ones (Md1, Md2) and one at the apex (Ma), but there may also be additional minor ones. The pinkish patches are also broken by the positions of the dots, with, in niasica, three patches distal to the postmedial, the largest (PMa) being the most anterior and the smallest (PMd) being that on the dorsum. There is a smaller triangular patch (T) between PMa and the central one (PMc), just interior to the medial black dot of the distal margin. There are two patches in the medial zone, interrupted by white along the anal vein, and there is also a subbasal patch (SB) on the costal side of the interior antemedial dot. The anterior medial pink patch (AMa) is almost twice the area of the posterior one (AMp). The male genitalia in the complex have two spines laterally on each side of the tegumen directed away from each other as illustrated. The interior margin of the valve sacculus may be produced or angled, but is not so in niasica. The distal process of the valve is usually bilobed or bifid; in niasica there is a bluntly triangular process on the costal side and a rounded lobe ventrally (it is recommended that the valves be spread and flattened out to ensure consistency in viewing of these processes). The cucullus is flimsy, narrow, sparsely setose and variable in length (relatively short in niasica). The aedeagus vesica encloses a massive and complex sclerite, usually tongue-like or spoon-shaped, often with smaller spines associated with it centrally. In niasica the main sclerite is simply tongue-like, usually with two spines over its centre. The female genitalia have the lateral pouches with a short horn on the interior face incurved towards the centre. The sclerite in the neck of the corpus bursae is large, ovate, giving rise to two unequal spines hooked in the same direction.

Taxonomic note

The type material of niasica has not been examined, but a male from Nias (slide 21335) has genitalia as described above, though the two interior postmedial dots are unusually large, and a female (slide 21184) lacked genitalia in its abdomen. The illustration in the  original description shows the line joining forewing black dot Pd2 to the satellite dot on the dorsum to run obliquely as discussed under the next species. When present in atrigutta, it forms a right-angle with the dorsum (e.g. in the lectotype). The wingspan given in the original description (18-22mm) is greater than that seen in atrigutta.

Geographical range

Borneo, Peninsular Malaysia (Penang), Nias and Mentawai Is., Java.

Habitat preference

This is the commonest species as recorded in recent surveys, occurring in a wide range of forested and disturbed biotopes in the lowlands, the highest record being from about 600m.

Genitalia: