THE HORSE BOT FLY.

Otago Witness, Issue 2087, 22 February 1894, Page 5

THE HORSE BOT FLY.

When the codlin moth, was a now iusect plague iv New Zealand, it seemed to attract the attention of every pewon, however remotely they might ba connected with horticultural matters, and quite a number of entomologists of a new school seemed to spring up in all directions, each ready with some wonderful story or another relative to thi3 insect; but now that the horse botfly has appaaredit seems to have put the poor codlin moth entirely in the shade, and we hear nothing now except extraordinary taels of the doings of the bob fly, and the awful deeds yet in store for U8 from that terrible enemy of mankind. As a matter of fact, the absurdity has been carried quite far enough, aud what the public should require bow is some reasonable proof of the truth, or rather the correctness, of the stories told of the bot fly. Mr French says that mere assertion is ne proof, and there certainly should be a little of the latter before the horse bot fly mania goes much further. In the actual presence of such annoying pests as the codlin moth and the destructive Hessian fly, one need hardly fret much about a few bot flies more or less, as in a very Bhort time we shall hear little about them, and hardly know whether they are here or not. On the other hand, if we do nob look after the Hessian fly, we may miss our wheat crops. Now is the time when stubbles should be clean burned off, and then ploughed carefully under with a akim coulter, and a little seed sown, so as to f arnißh a green crop for sheep to eat off by-and-bye, and so entrap what there may be of the pest in that second crop. Not very long ago a piece of the skin of a horse's stomach was exhibited in aa Auckland chemist's shop window, with a numbsr of bot fly larvje attached to it. As some people expressed it, the stomach was "full of the holes these insects had eaten through it " ! Now, every economic entomologist knows that the bob fly larvae leave marks behind them in the walls of a horse's stomach, which are very apt to be baken by inexperb examiners for holes perforated through ; bub are nob, and which could nob be the cause of deabh to bhe horse. Farmers as a rale know a good deal about horses, as they have a greab deal to do with these useful animals ; but because a man is an experienced practical farmer, it does nob by any means follow thab he aa such should be qualified bo act as a judge on a post mortem examination, and say whebher the horse has died from the acbion of bot fly larvce or not. Before we are jusbified in believing bhat all bhe beaching of the past, ever since the beginning of entomological research, and all the results of the experience and careful investigations of such men as Dr Thompson, are tobal errors, bo be discarded for bhe mere opinions of people who do nob even prebend to any knowledge of either enbomology or bhe veterinary art, it is only reasonable to require that something more reliable than the opinion of bhe experienced farmer should be advanced. The last assertion respecting the murderous propensities of bhe CEstrus gastrophilua equii (equii) is bhab it has killed a bull ! bub there probably may be some doubts whether the bull did nob die from swallowing the grindstone, and bhus having the bottom punched out of his stomach ! A specimen of thefly transmitted [from "D. G., Gore," arrived in good order, being packed in a strong wooden box where the post office stampings could not reach ib. The fly is certainly a horse bot fly. Ib is a female, and was probably in the acb of ovipositing when captured by the sender, who gives a very interesting account of the affair, and whose remarks upon the fly are very instructive, and ought bo be a lesson bo others who write occasionally on such subjects. The fly is not the common CEstrus gastrophilus equii, and differs from ib just as pointed out by bhe sender. Ib is considerably smaller, and bhere are cerbain technical distinctions in the neurations of the wings. It is very probably the Nasales, but the writer is not able at the moment to lay his hand upon Mr Skuse's little work upon the wings of dipterous flies, without which he could not undertake to determine the quesbion boo positively. It would, of course, be easy to forward the fly, and have the matter determined, but it is hardly necessary, because we all know that there is a great abundance of bhe genuine fly here in New Zealand, and bhab the horses are being acted upon in very great numbers, and that bhe only quesbion in dispute is not whether the fly ia here, or whether the larvae are in the stomach of bhe horses, but whebher bheir attack is fatal to the animal. In favour of this latter idea we have the opinion of a great many persons who do not even pretend to have studied the subject, as against that of a large number of experts on enbomology ever since the science has been known, and also a great many very capable veterinary surgeons who have given their special atbention to the matter, and reported the results of thousands of careful post mortem examinations. The question is, afber all, a very simple one so far as the horseowner is concerned. There is only one thing that can be done, and that is to look out for the first appearance of the eggs upon the hairs of the horse. They are very easily seen, and when found should be rubbed over with a cloth smeared in a kerosene emulsion of altol4or Ito 20 ttrength. This will be nearly sure to kill every grub contained in the eggs, and ib will also preveut bhe horse from licking bhem with its tougue ; bufc, after the grubs have gained the stomach of the horse, there is no medicine bhat can kill or expel them, and it is useless to try to do so, or, for that matter, to vex yourself about it, because they will nob remain there long enough to do bhe horse any fabal injury, although if they are in very large numbers they may cave c a sufficient amouub of irribabion bo bemporarily affect the animal's health to a slight degree, in which case ib may be as well to have resource to the same remedies as would be applied had the illness been caused by any other of the usual means. Some codlin moth enemies have just been received by the writer, but, with other topics, they will have bo remain to be noticed until next week's issue.