THE WARBLE FLY.

Ashburton Guardian, Volume XXXIX, Issue 9631, 11 June 1919, Page 6

THE WARBLE FLY.

It is satisfactory to learn (writes .the Medical Correspondent of the London •' Times") that tho Government are taking steps to deal with tiio pest of warble ily, which, as is well known, is responsible every year for great damage to the meat and hides of cattle in this country. A scieiitilk' sub-committee lias been unpointed to supervise and control experiments which are to ba carried out j in different pares of the country to discover, if possible, means of eradicating the pest. The amount of damage done by the Ily is so considerable that the -"Lancet,! 1 vvliioh ,discusses this matter fit lengili, estimates it at " upwards of £J400,(H.10 ' annually in this country aioue, for hides, in addition, the meat is much deteriorated, owiug to the presence iv it of cysts of the fly maggot. • The animal sulfors considerably in its general heart] 1. Tlie methods and habits of the ily are exceedingly interesting, and their discovery constitutes one of the many detective romances of modern biological science. The female ily attacks the herd of cattle —causing great excitement among the animals by her presence —and deposits her eggs on the hairs of the legs or lower parts of the body. The eg^-i Lave three days to hatch out, whereupon the small maggot which is born creeps aiuiig the hair to tin. 1 skin, and' burrows its way to the blond.' It eventually reaches the throat of the animal, perhaps by meant: of thy blood-stream. Thy idea that the cattle licked the maggots from their iegs was proved to be wrong, as muzzling. dm not pi-event the pest from reaching the throat. The maggots which were born in spring appear in. the wall of the throat towards the autumn, and stuy there all winter. In March they begin to migrate, passing along the animal's back, through the tissues. Sometimes they enter the spinal canal, from which they again emerge near tho tail. In any case, they then establish themselves near the surface and produce a cyst or '■ warble-," with a hole through the hide for breathing purposes. The maggot develop* iv this cyst, and finally falls out of it to the ground, where it becomes'a chrysalis, from which the new ■fly is (l:"/elopo.d. Tin 1 holes in the hide and the cysts in the muscles of the animal's back constitute the damage.