Art. II.—On the Appearance of Anosia bolina in the Wellington District.
[Read before the Wellington Philosophical Society, 22nd November, 1898.]
It will, I am sure, be a matter of interest to entomologists to hear of the appearance of this beautiful species in the Wellington District. A fine specimen (male) was taken in the early part of May of this year close to the Papaitonga Lake (which, I may mention, is some two or three miles to the westward of the Ohau Station, on the Wellington and Manawatu line). A Maori lad noticed it on the wing, and, being struck by the unusual brilliancy and beauty of the butterfly, gave chase, and succeeded in capturing it. This piece of good luck was, no doubt, due to the fact that it was late in the autumn, and a bitterly cold south-east wind was blowing from the adjacent Tararua Mountains. This had probably a benumbing effect on the butterfly, and limited its powers of flight, for the Maori boy was able to run it down without much difficulty, and on its alighting, with wings erect, effected its capture without in any way damaging the specimen. In his anxiety that I should receive it alive, he kept it imprisoned in a small box for some days, feeding it on moist sugar and honey.
My father, on a recent trip to the Fiji Islands, captured some twenty or thirty specimens of the South Sea Island type of this butterfly, and he noticed that it was ever on the alert, and so vigorous a flier that to take it on the wing meant a long chase with the net. He observed that it particularly affected the plantations of taro, on the tender leaves of which the larvæ may possibly feed. As far as I am aware, this is the first record of its appearance in the Wellington District. The natives, who took a considerable interest in its capture, told me that it was the first of its kind they had seen, and they are, as a general rule, most observant in matters of natural history.
The Rev. Richard Taylor, in his book, “New Zealand and its Inhabitants” (published in 1855), speaks of “a fine large butterfly” being found in the Middle Island, closely resembling the English “Purple Emperor.” In his later edition—1870—he figures it as Diadema arge, and characterizes it as being “the rarest and finest of our butterflies,” but makes no further mention of its habitat.
It has been thought by some to be an introduction into this colony from the South Sea Islands, but I think this theory can scarcely hold good, for at the time the Rev. Mr. Taylor first makes mention of it—1855—there could have been very little, if any, communication with the Fijis.
On comparing the specimen with my Fijian series, I find that it is appreciably larger than the island form, its measurement from tip to tip being 3 ⅞in. Out of twenty male specimens of the island form, the largest measures 3 ¼ in. and the smallest 2 ½ in., the rest of them giving a fairly uniform measurement of 2 ¾ in. to 3 in. I notice, also, that the buff-coloured bar on the under-surface of the secondary wings is considerably broader, and the small pale-blue ocellated spots on the under-surface of the primaries somewhat larger, than in its Fijian congener. I should think it is quite entitled to rank as a distinct race of the species, and to take its place accordingly in our list of Rhopalocera.
Since writing the above I have been fortunate enough to add two more specimens of Anosia bolina to my collection. They were both taken by Mr. J. B. Mackenzie, in the Nelson Province: one—a battered male—-was taken on the wing, after a long chase, at Motueka, early in February of this year; and the other, a female, at Kaitiritiri, near Motueka, towards the end of April. He tells me that he found the latter fluttering feebly at the foot of a high cliff, having apparently been beaten down by the wind.
One—a male—has recently been, taken at Picton by Mr. F. W. Andrews, and presented by him to the Colonial Museum. On comparing it with mine I find that it almost corresponds as to measurement, being only a shade smaller. This rather goes to show that the local capture is not of abnormal measurement, and it indicates a persistence as to size in the New Zealand form as compared with that from the South Sea Islands. I should state, however, that the male taken by Mr. Mackenzie is somewhat smaller than the Ohau and Picton examples, though noticeably larger than any in my Fijian collection. The female taken by him measures 4 in. from tip to tip, and is most vivid in colour.
Mr. G. V. Hudson tells me that solitary specimens, ranging over a period of twenty years, have been taken in Auckland, Napier, Nelson, Wakapuaka, and Collingwood, and one seen in Christchurch. So far it would appear, from recorded captures, that it principally occurs in the northern portion of the South Island, although at all times a rare butterfly.