New Zealand Department of Agriculture.

Manawatu Herald, 11 July 1895, Page 3

New Zealand Department of Agriculture.

JOHN D. RITCHIE, Secretary.

LEAFLETS FOR FARMERS, No. 20.

By T. W. Kirk, F.L.S., &c, London.

Figs. lio 8. Maggot in various stages of Perfect Fly. Fig. 6. Section of cell of Piece of tanned leather, showing dainai

liuckily this insect has not, so far A8 it ; Isnown, appeared in New Zea~ land yet, but one or tWo ca3es have been discovered in Australia in cattle recently imported from England. Unite4 action has been taken by the varibus'Chief Inspectors of Stock in the Australasian Colonies to urgo upon the Agents General the neces* iity "for . instructing; the veterinary officers whose duty it is to pass all oaitle for these colonies to make ■peeial, examination in order to ascertain, if any of them are infected. All animals are also carefully watched while in quarantine, but it is difficult to detect the presence of _the grub in the early stages, and it tjg therefore thought desirable to publish drawings and description?, in order ..that settlers may become familiai';with the appearance of the inseetiJfind so, being forewarned, forearmed.

In order to understand the loss which would follow the introduction of this terrible pest it is necessary to give briefly the life-history, as ob lerved in the United Kingdom.

The eggs are usually laid during (be months of June, July, and August, The female fly, which is protided yvith a very strong ovipositor, Beleots, if possible, a young beast, And, alighting on the back near the spine, manages to pierce the skin and deposit a single oval egg in the hole. Tbii operation is repeated till all her eggß are laid. After a time the eggs hatch, and tiny, worna-like maggots emerge. The gradual growth and movements of the grubs cause inflamation, and produce ." tumours " or warbles. The grubs are found withiu these warbles, head down, the tail, provided with breathing«tubes, being pressed against the opening.

development. Fig. 4. Chrysalis. Fig. 5. warble i n hide (after Miss Omerod). Fig. 7. ;e done by warbles (from nature).

Approaching the last stage (Fig. 8), they press constantly against th« openings, which are thus enlarged sufficiently to allow the exit of the grubs. These fall to the ground, where, like the maggots of the horsebot, they wriggle into the earth, or under any available shelter, and pass iuto the chrysalis stage (Fig. 4), from which within a month the perfect flies (Fig. 5) emerge. The fly has bat two wings. The head and front part of the body are yellowish, the back portion of the body black ; the abdomen 19 banded white, black, and yellowish. One specimen in my possession measures just three-quarters of an inch in length. It will be seen that not only does this fly ruin the hide, but it also in» jures the health of the beast, and causes it to lcse condition. A correspondent states that the annual loss in the United Kingdom from this cause alone amounts to several millions sterling.

At Home it is a common practioe to pqueeze out the grub from the cows' backs, and to apply various compounds of tar and sulphur as preventives ; but this can only be done where the herds are limited. Should the pest ever arrive in this country some other raean9 of preventing the attack will have to be reported to, and no better or easier plan could be devised than that recommended for protecting horse from the horse-bot— namely, yarding the animals and spraying them with carbolic mixture. No "fly will touch them while the effects last.