ENTOMOLOGICAL.

Otago Witness, Issue 2051, 15 June 1893, Page 4

ENTOMOLOGICAL.

Icerya Purehasi at Wellington. This dreaded pest, after visiting several of the provinces in New Zealand and doing its share of mischief, has now made its appearance at the capital, and has given alarm to the fruitgrowers and horticulturists of the neighbourhood. The natural result has of course been an application for the pestis' now well-known and inveterate enemy, the pretty little ladybird beetle Vedalia cardinalis. It is rather singular, and somewhat fortunate too, that at the same time the application for vedalia reached the i writer a letter was received from Mr R. Harding, the Crown Lands Commissioner of Napier, to say that vedalia were at the present time so abundant in the Hawke's Bay district that a person could now collect as many as Mr Koebele did some years ago in the same time, and as Mr Koebele collected 6000 of these beetles in three days, even allowing a very wide margin there will be no difficulty in supplying Wellington with a sufficient contingent to give a good and very speedy account of the enemy. There is something very curious and interesting in the history of these two opposing insects. In Hawke's Bay district, as in many other places, the scale broke out and increased to such an extent that vegetation seemed quite white with it and plants died in all directions, being sucked to death. Then vedalia appeared, imported doubtless by chance, and apparently exterminated icerya. As has been frequently mentioned in this column, it is supposed that this beetle feeds upon nothing else, and consequently when all its means of subsistence were exhausted it died completely out and could nowhere be found. Naturally enough the scale, which in its larval state is very active, and which feeds upon any plant, managed to survive to a small extent, and as it breeds very rapidly it became again a formidable pest. This was just what all entomologists expected, and what has always taken place ; but the fear was that vedalia would not reappear. It seems, however, that the insect must have some means of subsisting that we are not aware of, because its revival at Hawke's Bay is only one more instance of what has taken place in other countries. When the writer was employed by one of the Australian Governments to lopk more closely into the habits of these two insects he found that vedalia on being introduced into an icerya infected district increased with the abundance of food in a truly astonishing manner— so rapidly, in fact, that it could not be credited except by those who have witnessed examples of it. They swept (so to speak) over the masses of the scale, apparently leaving behind them nothing but dead scales and torn and empty ova sacs. A closer examination, however, showed that in & great many instances a very few (sometimes only three or four) eggs were left undevoured, these being situated invariably under the body of the mother scale, and amongst the "fluff" of the cotton, instead of being, like the bulk of the eggs, inclosed in the bag. On sending some of the vedalia alive to Mr French, the Victorian Government entomologist, that gentleman placed several with some of the "mealybugs" (Dacty lopius), and he found that, although they were evidently very hungry and attacked the bugs, they did not devour them. A closer inspection with a glass showed that the "fluff" on these disgusting pests caused entanglement of the legs and jaws | of the vedalia, and saved the bugs from being eaten, and the same, no doubt, is the reason why they do nob devour those few protected eggs of the cottony scale, and thus enable the pest to preserve its existence. Now, however, that it is proved that the beetle will also survive, and be on hand again when wanted, we can be easy as to the ravages of the scale, and feel assured that that most terrible scourge of all vegetation will never again play the havoc it has done in California and the Cape of Good Hope, and even to a lesser extent in Auckland, Nelson, and Hawke's Bay. Insect Predictions. Some of our wise astronomers are continually predicting the extinction^ the sun, the destruotion of our globe, or some such great catastrophe, which fortunately has not yet overtaken us, and probably never will. Professor Le Compte has, however, been warning us of a species of dire destruction in quite another direction. He says that the frightful increase of all kinds of insects will ultimately lead to the total destruction of the entire vegetable world, after which man will become their prey. "The earth will then be a gigantic parish of plaguemines, in which the mosquito tribe will (rule supreme, until some other equally obnoxious vermin shall arise and devour them." Commenting upon these anticipated misfortunes an American paper observes that the human race must decidedly be in a tight place, but that if the sun is going to be snuffed out like a candle and the earth exploded like an old steam boiler, we may as well try to look upon such minor evils as the universal prevalence of vermin as something that cannot be cured. Itis'afact, of course, as everybody knows, that there are a great many of both insects and other animals whose increase is so rapid that were it to go on unchecked the world would some day not be large enough to hold them, and all that is in it too small to feed them. But then_ this increase is always checked and kept within bounds in some way. To confine the question to entomology, we see continually such enormous numbers of certain kinds of insects that we are led to wonder where they all come from, and then they all disappear as suddenly as they came. This is very often the case with crickets, grasshoppers, and Buch pe6ts, which appear and disappear in the most unaccountable manner. The writer well remembers many such cases, and especially one instance in which on going into a hayfield, the haycocks, the ground, the tools, and everything was completely covered with a light web, and infested with such inconceivable numbers of very small spiders that the people were almost afraid of them, but before noon they had completely disappeared, and were never seen again. Besides those sudden checks received by fast-increasing insects for which we are not always prepared to account with certainty, there are others which we can very easily understand and of which we should avail ourselves. Entomologist. A considerable portion of Mr Allan M 'Lean's fine conservatory near Waimate, and a fine collection of flowers, was destroyed by fire. The best medical authorities acknowledge the value of Ayor's Pills, and prescribe them with the utmost confidence aa the most effectual remedy for diseases caused by derangements of the stomach, liver, and bowels,