Summary And Conclusion
Apparently D. selenophora is not a native of New Zealand and must have been introduced from Australia originally.
The usual appearance of the moth is given as January, February, March and April.
Hudson says hibernated specimens are sometimes found in October and November, the months in which the present occurrence has taken place.
The larvae feed on Acacias and these trees are planted in many parts of Southland.
An examination of Acacias near and in Invercargill failed to reveal any larvae.
No Acacias are present in the Milford district so far as I am
aware, but the kowhai (Sophora microphylla) and various species of Carmichaelia represent the Leguminosae.
The antennae in the males are ciliated. All the specimens received at the Southland Museum are females and one deposited several scores of eggs in the tin in which she was confined.
The question arises as to how the present occurrence of this moth has taken place. Three solutions seem feasible and any one might suit the present case:—
1.That the moths may be hibernated individuals as described by Hudson. The dry summer of 1937–38 and the comparatively mild winter and early spring following would be favourable in this respect. The date of the occurrence is as given by Hudson.
2.That the moths may have arrived here by flight from Australia, in which case one would expect to find them in the Milford district, the nearest land in New Zealand to Tasmania and Eastern Australia.
3.That the eggs of the moth may have been introduced by some means and the resultant growth of the larvae and the metamorphosis taken place in this country. Hardwood poles from Australia are often landed at the Bluff, and the eggs, which are small and seed-like, could be introduced in this way.
Without further knowledge, the question must remain unanswered, and it will be interesting to see if a large hatch takes place from January on in 1939, for many moths must have had opportunity to deposit their eggs, and the number captured probably represents a very small percentage of the total present in Southland at this date.
Since writing the above I have received five more specimens on the following dates:—
|22/11/38||Three specimens, one from South Hillend, and two from Te Tua||3|
|24/11/38||Two from Gladstone||2|
This brings the total up to 34, and Dr. Burns-Watson has reported to me of the presence of several more. I was also told by a friend that the conductor of the Children's Session at Station 4YA, Dunedin, has received a great many more from various parts of Southland and has been giving a radio talk on them during a part of the programme. I have since verified this report.
I was told about the same moth whilst on a visit to Stewart Island in March, 1939, and identified a specimen as D. selenophora. The time of the appearance on Stewart Island coincided with that on the mainland. Further evidence came to hand of the appearance of the moth in the Milford Sound district, but no specimens were forthcoming, although my informant described the moth and readily picked it out when shown a tray of mixed moths.
A close watch was kept in many parts of the Province during January, February and March of this year (1939), but no specimens were seen or heard of.
I tried to hatch out eggs laid by some of the specimens sent in to the Southland Museum, but was unsuccessful.