This is a very obscurely marked insect, closely allied to the next species, from which it can only be distinguished with difficulty. Its somewhat smaller size and the two minute white dots on the reniform stigma appear to be the most definite characteristics.
The perfect insect appears in May and June.
Described and figured from specimens in Mr. Fereday's collection.
MELANCHRA VITIOSA, Butl.
(Apamea vitiosa, Butl., Proc. Zool. Soc. Lond., 1877, 384, pl. xlii. 3. Mamestra ochthistis, Meyr., Trans. N. Z. Inst. xix. 20. Mamestra vitiosa, Meyr. Trans. N. Z. Inst., xx. 45.)
(Plate [IV]., fig. 42; Plate [III]., fig. 16, larva.)
This is a scarce species in the neighbourhood of Wellington. In Christchurch it is very common.
The expansion of the wings is 1⅜ inches. In general colouration it closely resembles the preceding insect, but is considerably paler, with the markings much more distinct. There are no clear white dots above or below the reniform stigma, the orbicular is obliquely oval and rather conspicuous, and the claviform is strongly margined with black.
The larva is rather robust, very pale green above with numerous white lines and dots; dark green beneath with yellow dots. In the light part there is a triangle of black spots on each segment. The young larva has a strong pink lateral line, but in mature specimens this line is confined to the anterior and posterior segments only. Length when full grown about 1¼ inches.
This caterpillar feeds on Melicope simplex, and when amongst the foliage of its food-plant it is extremely hard to detect, owing to its protective colouring and sluggish habits. The larva is full grown about October.