16 NEW ZEALAND MACRO-LEPIDOPTEBA. 



MELANCHEA INSIGNIS, Walk. 

 (Euplexia insignis, Walk., Suppl. 724. Xylina turUda, ib. 754. Mamestra polychroa, Meyr., Trans. 

 N. Z. Inst. xix. 16. Mamestra insignis, Meyr., ib. xx. 45.) 

 (Plate IV., fig. 29 S , 30 5 .) 

 This pretty species has occurred at Palmerston and Wellington in the North Island, 

 and at Blenheim, Christchurch, and West Plains near Invercargill in the South Island. 

 It is probably common and generally distributed. 



The expansion of the wings is about If inches. The fore-wings are pinkish-brown ; there is a 

 short black streak near the centre of the wing at the base, and an irregular, extensive black marking 

 along the dorsum; the orbicular, reniform, and claviform spots are large, margined first with green 

 and then with black; a fine white line is situated parallel with the termen, edged with green, and 

 emitting two sharp tooth-like markings ; beyond this line the ground colour of the wing is dark- 

 brownish-black. The hind-wings are dull brown, darker towards termen; the cilia are white with 

 a brown line. The antennae of the male are slightly bipectinated. In the female the ground colour is 

 considerably paler, the black markings much darker, and more suffused, and the posterior half of the 

 reniform is usually creamy-white. 



Some specimens have the green and black markings slightly more pronounced, 

 but otherwise there are no important variations. 



The eggs are deposited in October and November. When first laid they are pale 

 greenish-white, but become dark brown in the centre as the enclosed embryo develops. 

 The young larvae emerge in about a fortnight. At this time the two anterior pairs of 

 prologs are very short, causing the caterpillar to loop up its back when walking. In 

 colour the young larva is pale brown, with numerous black warts emitting several long, 

 stiff bristles. It is very active, and busily devours the soft green portions of the dock 

 leaves, leaving the harder membrane untouched. Twelve days later the larva becomes 

 pale green in colour, and moults for the first time, after which traces of subdorsal 

 and lateral lines present themselves. Growth then proceeds with great rapidity, and 

 in another eleven days the larva again sheds its skin. The last moult occurs a fort- 

 night later. 



At this time the larva is pale greenish-brown, inclining to yellow on the ventral surface. The 

 lateral lines consist of a series of black markings near the posterior margin of each segment ; the 

 subdorsal lines are represented by four oblique black marks on each side of the four posterior 

 segments of the larva. The region between these lines is much clouded with yellowish-green or 

 pink, the larvae having a tendency to diverge into pink and green varieties. The anal segment is 

 dull yellow. The head is brown, with two black stripes and several black dots. 



Whilst rearing these larva' I noticed that during the daytime they invariably hid 

 themselves under the blotting paper at the bottom of the breeding cage. Mo doubt, 

 under natural conditions, they retreat beneath the ground, only coming abroad at night 

 to feed. This habit would account for the difficulty experienced in finding larvae of 

 this genus in a state of nature. 



The pupa state is spent in the earth, and occupies about it month. 



The moth appears towards the end of January. It evidently hibernates through 

 the winter, as it is often seen very late in the autumn, and is always one of the first 

 moths to come to sugar in the early spring. It is frequently observed at rest, on fences 

 and trees in the daytime. 



