Imperial White Butterfly, Delias harpalyce

Plate 9. Pieris (Thyca) harpalyce (now known as the Imperial White Butterfly, Delias harpalyce)

The present species is remarkable for the extraordinary habit of spinning a large white silken sheet like a tough cobweb on which to attach the pupæ in large groups of very numerous individuals closely placed side by side.

As Mr. Wallace has noted that certain islands north of Australia have the individuals of the species of white butterflies distinguished from the individuals of the same species found in other islands by the greater or less acute pointing of the tip of the upper wing, it is interesting to note that in this species, although the upper wings of the male are more angulated or less rounded that in the female, yet the amount of straightening of the outer edge and consequent angularity varied in different individuals of the same brood.

Common everywhere in Victoria, flying at moderate heights about the she-oak trees (Casuarina), and occasionally visiting gardens.