Philpott. — Protective Resemblance in N.Z. Moths. 217 



Venusia undosata. 



This beautiful moth is attached to the pepper-tree {Drimys 

 colorata) ; the lemon-coloured fore wings of the typical form 

 with their dark - brown costal borderings harmonize in a re- 

 markable manner with the leaves of this plant. There are, 

 howevei", a gi'eat many striking variations of this insect, one 

 in particular having developed a most inconspicuous drab 

 colour. 



Xanthorhoe. 



In this genus a noticeable case of colour - development to 

 suit environment occurs. X. orcphyla is almost exactly similar 

 in markings to X. seynifissata, but while semifissata is pinkish- 

 brown, orophjla is bluish-grey. While semifissata frequents open 

 forest districts, orophjla is found on the mountain-ranges, and 

 its colour is well adapted to the rocky nature of its habitat. 

 It is, I think, probable that X. orophyla has been developed 

 from A', semifissata, and this is the more likely as some forms of 

 semifissata vary in the direction of the grey colour of orophyla. 

 X. clarata presents a case of the protective colouring being 

 chieflv developed on the undersides of the wings. This form is 

 very conspicuous and striking in the cabinet, but when resting 

 with folded wings amongst the tussock and rough herbage of 

 its natural surroundings it is far from easy to see. The insect 

 folds its wings over its back, and the undersides are covered ^vith 

 dark elongate dots on an ochreous ground, a type of marking 

 very suitable to its ordinary environment. In A', hulbulata we 

 have an instance of " contrast colours." The bright - orange 

 hindwings, conspicuous in flight, are in strong contrast to the 

 dull-grey forewings, and when the insect suddenly drops into a 

 tussock and closes its wings it is hidden at once ; that which 

 on the wing appears to be a bright-yellow insect is instant- 

 aneously transformed into a dull and inconspicuous grey one. 



Notoreas. 



The members of this genus, with Lythria and Dasyuris, are 

 for the most part protected by " contrast colours." The genera, 

 however, contain forms, such as A'^. perornata, in which the 

 fore- and hind-wings are alike brilliant; and others, as N. omi- 

 chlias, in which almost all trace of bright colours has been lost, 

 and the insect is admirably protected by its resemblance to 

 the general hue of its environment. There is still, however, 

 much to be learned of the habits of these mountain forms, and 

 future investigations may throw considerable light on their 

 economy. 



