On five species of the genus Hypena Schrank described by Wileman from Japan : Lepidoptera, Noctuidae

Abstract

The genus Hypena Schrank, a large homogeneous group of the world-wide distribution, contains a number of species of subtropical origin. Most of these species appear to show considerable variations in forewing pattern subject to seasonal conditions. Four species dealt with in this paper fall into this category ; the moths appearing in June to August are much stable in pattern with scarce difference between the sexes, but those in autumn are more or less variable than the summer form especially in the female. The latter often looks much faded after overwintering. Correct identification to the difficult complexes of this genus would be secured by giving light on these points of view. Hypena indicatalis Walker, 1858 =Hypena caliginosa Wileman, 1911. Syn. nov. The female has the antemedian line oblique to before postmedian line and acutely angled at vein 1, which in the hibernal form markedly defined with pale to form a large median triangular patch (Fig. 11, 12). In my collection there is a darkest female specimen (Fig. 13) fairly agreeing with the holotype of caliginosa Wileman (Fig. 2). This rare form is to appear in the hibernal generation. Caliginosa Wileman is a synonym of indicatalis. Common in the southern coastal to south-western regions of Japan. Larva feeds on Boehmeria. Elypena occata Moore, 1882 =Hypena hampsonialis Wileman, 1911. Syn. nov. The ground colour of forewing varies in the hibernal form from pale ochreous yellow to dark bluish grey; the blackish mark below apex in cellules 5 and 6 are often reduced or vestigial (Fig. 16, 17). Common in the southern coastal to south-western regions of Japan. Larva also feeds on Boehmeria, frequently found mixed with that of the preceding species (Yamamoto, 1965). Hypena innocua Wileman et West, 1930. The male antenna bears ciliation much longer than the two preceding species ; the shape of forewing is almost similar to occata. In the hibernal form the black dots in and at end of cell more prominent; the subterminal series of blackish dots and dark oblique stria below apex in cellule 6 are clearly marked (Fig. 18, 19). In one male (Fig. 21) the forewing is strongly irrorated with fuscous, and another female (Fig. 22) has a large medial triangular patch. This last appears to be the same as described as Hypena triangularis Moore, 1882, from Khasia Hill and then it take precedence to innocua Wileman et West, but I am premature to conclude this synonymy. Not uncommon in nearly same region of Japan as occata. Lavra unknown. Hypena sinuosa Wileman, 1911. The male antenna is as in the preceding species. In this species the sinuous postmedian line is distinctive. The dark shade before it is variable, often reduced into two spots at end of cell and at vein 2 (Fig. 26) or completely obsolete (Fig. 23, 24). Wileman's type series are from Kagoshima, Kyushu, but the materials I have examined come from Yakushima I., Tanegashima I., Ishigaki I. and Taiwan. Two overwintering females collected on Ishigaki I. are markedly tinged with red brown, one of which is ornamented with double irregular series of dots before subterminal line of forewing (Fig. 27). Larva unknown. Hypena furva Wileman, 1911. This species is not represented in my and other available collections. The holotype specimen (Fig. 6) is a male collected at Kagoshima.