About the middle or end of February these larvæ generally bury themselves in the ground, where they are transformed into pupæ. They remain in that condition until the following summer.
The pupa is about 2 inches in length and is of a dark mahogany-brown colour. It is furnished with a large curved process, projecting from the lower side of the head, and containing the enormous proboscis of the future moth.
The perfect insect appears in November and December. It flies with incredible velocity at evening dusk, and is often observed hovering over flowers, and whilst poised in the air above them, extracts the honey with its long proboscis. Mr. A. P. Buller has very kindly furnished me with the following interesting notes on the habits of this species, as observed by him in the Auckland district:--
"During the summer of 1879 I came across _S. convolvuli_ in great numbers, near Ohinemutu, in the Hot Lake district, frequenting at dusk a tall, delicately perfumed meadow flower (_Oenothera biennis_, commonly called the evening primrose). They were to be seen on the wing soon after sundown, and on warm, still evenings literally swarmed. It was an extremely pretty sight to watch their rapid movements as they darted from flower to flower, never alighting, and keeping up a constant vibration of their wings as they probed the yellow blossoms. They appeared to be extremely local, for I only met with them on a few of the grassy slopes round the shores of Lake Rotorua. I visited the same locality two years later, at the same season, and only occasionally saw one, although the evening primrose was in full bloom at the time. In 1882 I captured several at flowers of the trumpet-tree (_Brugmansia_) in a garden near Auckland. The same summer I found large numbers of the larvæ at Waiwera (near Auckland), on a species of convolvulus growing in profusion on the sandhills in the vicinity. Although the larvæ were so abundant I never came across the perfect insect. I obtained some twenty or thirty of the pupæ, but unfortunately was never successful in hatching out the imago. As far as my knowledge goes, this beautiful moth is confined to the Auckland and Waikato districts, although I have heard of a single specimen being taken in Hawkes Bay."