ENTOMOLOGICAL.

Otago Witness, Issue 2086, 15 February 1894, Page 5

ENTOMOLOGICAL.

By R. Allan Wight, M.A., A.E.8., &c.

The Bicanla Dlscalls (Walker).

A lady signing herself " M. T." has been kind enough to transmit to the writer a piece of a plant covered with small insects, accompanied with a request that I Bhould inform her what "these beetles" are called, and if they are injurious or useful. She adds, by the way, should they be designated as "beetles," or " bugs " ? The plant enclosed with the insects is a piece of phlox about 4in long, and there are upon it from 35 to 40 of the little creatures, each with its Bucker at work pumping up the juica of tbe plant. They are neither beetles nor bugs, properly so called. A beetle is an insect of the order coleoptera, which are easily distinguished by having the wings (that is, the proper membranous wings) protected by outer hard wing cases or coverings; but a bug, properly so called, is an insect of the order Hemeptera (or " half winged ") and sub-erder Heteroptera, which means "different winged. In America most insects are commonly designated as "bugs" in common parlance, and there these would probably be so called by the- uninitiated ; but they belong to an extensive family of the Rhynchota, and are known generally as ••hoppers." This one is the Ricania discalia (of Walker), and a specimen of it sent over td America some years ago by the writer was identified as such by Professor Uhler, of Baltimore, who may be considered the highest authority on this class of lnuectfl. These little insects first began to be noticed about Whangarei, in the North Island, several I years ago, and they continue to be found there in very great numbers upon most kinds of plants. They are not generally regarded as injurious insects, because the evil they do is not very conspicuous; but it is quite impossible to regard them in any other light when one considers their enormous numbers, and the fact that they are actively engaged m continually pumping up the, juices ot the plants upon which they swarm. These juices are immediately converted into a sweet fluid called honey dew, and showered over the leaves of the plants in such abundance that it drips from them as it the plant was being rained upon. The leaves thus treated soon become black, as the spores of a certain black fungus germinate upon the wet surface and probably cause very much more j serious injury than even the abstraction ef the Many people in Whangarei seemed disposed to think that patches of the fern were being killed by the little hoppers, bub the writer found 1 on careful investigation that the fern had been ! killed by a root fungus, called by Professor Kirk Lycoperdon gemmatum, and not by the hopper ; but ia some instances some of the more tender herbaceous plants, on which they were Bwarmiug, had certainly been killed by them. Some of the insects of this class gave rise to several very sensational articles being written in some of the American journals. It was observed that certain trees "wept" copiously, without ifc being possible to ascertain any cause, and this gave rise to all kinds of romantic ideas. Some people again thought they had discovered that certain willow trees possessed the power of absorbing through the roots water, which they afterwards shed as tears from the leaves. But an entomologist having examined a case of the tond, readily discovered the cause in the presence of vast numbers of these Rhynchotie. Should these insects become destructive they will have to be destroyed by some wash that kills by contact, as the depth from which they draw the juices would prevent poisoning by any substance applied to the surface of the plant. A wash of soft soap and water, with a small addition of soda or kerosene, would probably succeed in getting quit of them. One of the insects of this class has o% late been attracting attention by its ecopomic value in a rather singular way. It has been discovered by a United States bee owner that the sweet secretions of this insect are held in great estimation by the bees, which make very large quantises of a Buperior quality of honey from them. These secretions singularly enough are made from the resinous juices of the pine trees, and'this enterprising beefceeper has not been blow in ' • calculating " exactly how much honey is to be gained from a pine forest per acre with tho aid of these two insects, and he makes out that by proper care.a forest of these trees, of no appreciable value otherwise, can be made to yield a very good income. As yet the discovery has not been rendered practically useful (that is co far as we know), but it is a very interesting one from many points of view, and may in all probability become very useful in the course of time, when the industry has becomemore fully understood. In the meantime it is very interesting to contemplate the many and littleunderstood use's to which the creatures of a beneficent Providence can be put. The Horse Bot Fly Again. A box csntaining some insects (or parts of insects) has been received from D,unedin. It is a very light pasteboard pen box, and the post office people seem to have been uncommonly vicious when they stamped it, for the contents are sadly pounded. There are the remains of three common house flies, three abdomenal Begments otßome large fly, and a pretty large porv tion of one. wing of a large dipteron, the general appearanoe of which, and the neuration, answer to that of the horse bot fly, but the condition scarcely justifies a very positive identification. In any question, however, which relates to the bot fly in New Zealand it would very much simplify the matter to understand that there is no dispute of any kind as to the presence of the fly in New Zealand, where, on the contrary, ifc is now to be found in great abundance, with a wide distribution. There is also no question whatever about the larva) of the fly being found in considerable abundance in the stomach of our horses, adhering, as usual, to the coats. The only matter ia dispute is whether these larvse cause the death of the animal. Now the alarmists— who, by the way, are generally farmers or other persons practically acquainted with the horse, but neither expert veterinary surgeons nor scientific entomologists— st^te that the horse Is frequently filled Toy these insects, and occasionally' allege that th.ey have made 2 } ftst moxUm examinations, and proved (to their own satisfaction) that such is the oase, But the fly has been perfectly well kno*n and understood for a very long time, and neither the moat skilled vetermaries, who have given a great deal of attention to the matter, nor the entomologists, are of opinion that the pest causes the death of the horse, and u.nde? these circumstances the writer venture^ to express an opinipn that before the alarmist can expect his statements to be implicitly relied upon he should be prepared to aceopt the onus of proof, and bring forward a well-authenticated case, in which some well-known and experienced veterinary surgeon, accompanied by a qualified entomologist, is prepared to vouch that the death of the horse is clearly attributable to the action of the bat fly larviy. At all events the pest has now got such a footing in the colony that it ia impossible ever to expect to get rid of it, and another settled point it that for' the larveo once ad-

mitted into the stomach there seems to be no remedy known ; but it is a comfort to know that horses are not becoming extinct elsewhere, and that there is a very simple and effectual preventive remedy. A little diluted kerosene oil (emulsion) rubbed on those parts of the horse usually deposited upon has the effecb of hindering the fly from placing its eggs there, also of killing the eggs if they may be there already, and finally it keeps the horse from lickingthe places, and thereby conveying thelarvteon its tongue~to the mouth. Farmers and horseowners would do well then to attend chiefly to this last remedial course, and net allow themselves to be unnecessarily alarmed by a fear of what will never happen— but if they want either bot flies or any insects identified I would request that they may be sent in a stronger box, and the writer will be happy to oblige them to the best of his power.