Art. LVIII.—On the occurrence in New Zealand of a Species of Lepidoptera belonging to the Cossidæ family.
[Read before the Philosophical Institute of Canterbury, 1st June, 1876.]
In the month of February last, Mr. W. T. L. Travers kindly forwarded to me a specimen of a very large moth, recently captured by Mr. H. E. Liardet, at Wellington.
The insect is, unfortunately, in a very dilapidated condition, being almost denuded of scales, and having little more than half its wings remaining. It has, however, sufficient characters to identify it as belonging to the Cossidœ family; but as to species, or even genus, it does not appear to me to be clearly identical with any of those described in the “British Museum Catalogue,” the only descriptive catalogue available to me for reference. At the same time I imagine it must be a species comprised in that catalogue, as Mr. Fuller, the Taxidermist of the Canterbury Museum, informs me that he has seen hundreds of a similar moth about the gum trees in Australia, and therefore it must be very common, and its existence and description has doubtless been long ago recorded.
The length of the specimen, from the front of the head to the anal extremity, is 40 lines, and the breadth of the thorax 12 lines, the head being extremely small in comparison—not more than 4 lines in breadth. The expanse of the wings (if perfect) would be about 90 lines. The few scales remaining on the insect indicate its general colour to have been somewhat similar to that of Cossus ligniperda, but rather more hoary.
A similar specimen was taken in the pupa state by Mr. D. O'Brien, from a log of jarrah (Eucalyptus marginata), at Lyttelton, a year or two ago, and is now in the Museum at Christchurch; and, at the time of its capture, large logs of jarrah and other timber imported for the harbour works were lying there. On that occasion I went to Lyttelton purposely to see if there were any indications of the timber having been bored by larvæ, and found several perforations in size and character such as would be made by a Cossus larva.
That in both cases these insects have been introduced in timber imported from Australia there can be little doubt; and it shows the importance of instituting a careful supervision of all the timber brought into the colony from other countries.
The moth which I received from Mr. Travers was a female, and contained thousands of eggs; in fact, her abdomen was crammed with a mass of ova, which, had she been permitted to deposit, a new agent of destruction might have commenced its ravages in our forests. That other individuals of the same species have escaped from the imported timber is more than probable, and already the work of destruction may have begun.
I am not acquainted with the extent of injury done to the timber of Australia by this moth, but trees affected by Cossidœ larvæ are generally riddled with their perforations.
We are already suffering from other introduced pests of this description, e.g., œgeria tipuliformis, a moth whose larvæ are committing great destruction amongst our currant trees by perforating the branches and rendering them pithless and hollow.
Government inspectors should be appointed, whose duty it should be to carefully examine all imported articles subject to the attack of insect pests, for the purpose of ascertaining if any such pests are present, and of adopting means to effect their destruction.
There are probably many gentlemen in this colony who have resided in Australia, and been acquainted with the species of moth in question, and who might furnish information that would be a valuable supplement to this paper.