Imágenes de páginas
[graphic][subsumed][subsumed][merged small]

Where they appear in an orchard and attack a number of trees, no doubt the simplest plan would be to spray well with Paris green, and any odd ones left could be taken with the burlap.

The Grey-streaked Moth (Prodenia littoralis, Boisd.). About the first week of last April, the leaves of an apple tree in my garden at Croydon were all brown and discoloured, and upon examination, I found that most of them had been stripped of the epidermis, only the skeleton of the leaf remaining. Further search showed that the remaining leaves were covered with hundreds of tiny green semi-transparent grubs spotted all over with black dots, which were lying in rows along the surface of the leaf feeding in a similar manner to the sawfly larvæ. When picking off the infested leaves, I found several patches of eggs which were cemented together and protected with a covering of brown down, forming a convex excrescence upon the under side of the leaf. The eggs are very small, pearly grey, and beautifully striated; the contents of one patch when counted with the aid of a pocket lens comprised 1,356 eggs.

The young caterpillars grow very rapidly, and are very quick in their movements, dropping by a thread from the mouth when disturbed. They soon lose their bright green tint as they reach maturity. When full grown, they measure about an inch and a half in length, thick and cylindrical in form, narrowest towards the head, of a general olive green colour with the head dark brown; the segments are lighter coloured on the sides and undersurface, while along the upper half of the sides there is an irregular blackish band forming a triangular mark on each segment, with a stripe of lighter colour down the centre of the back.

The most forward of them were full grown in the second week in May, and disappeared in the earth at the bottom of the jar, where they underwent their transformation, about an inch below the surface, without forming any cocoon. The pupæ are dark brown with the head portion, and the wing cases small, with the body stout and cylindrical pointed at the tip, termi. nating in two pointed spines. Early in June the moths commenced to emerge, and it was wonderful to notice how their colouration assimilated with the earth upon which they rested with their wings closed, and perfectly motionless until disturbed. When first hatched out the moth holds it wings over its back like a butterfly, but as soon as its plumage is settled, it lies flat down among the dead leaves and rubbish.

The moth measures nearly 11 inches across the wings, the fore pair long, slender, and rounded behind, of a general dark brown colour, with a regular finely-barred edge, and the inner portion irregularly striped, with a number of very fine pencil-like grey lines, several of those in the centre crossing each other, the others short and transverse. The hind wings are pearly white, semi-transparent, with the nervures forming fine brown lines across them, and a stouter line round the outer edge.

Preventives and Remedy.-In the case of small trees, if noticed in time, the leaves could be hand-picked and the young larvæ destroyed, but care should be taken in picking them that the little grubs do not drop to the ground. In the case of large trees, a spraying would be very effective, as these caterpillars always seem to feed upon the upper surface of the leaves, If the caterpillars have left the foliage before their depredations have been noticed, the best plan would be turn over the soil beneath the tree and expose the pupæ. * A flock of hens or ducks, if turned into the orchard, would be most effective assistants in picking up all those overlooked.

Reference to Plate.-A, Moth ; B, Pupa; c, Caterpillar.

The Bovine Tick Fever.


The information contained in this compilation has been prepared at the instance and by direction of the Honorable the Secretary for Mines and Agriculture.

Mr. Sydney Smith has deemed it desirable to bring together, in the shape of a pamphlet, a summary of what information there is obtainable relating to the disease known as “Texas fever" in America, and which it is proposed to call “ Bovine tick fever" in the Colonies,

It has been decided that this information should be of a popular style, so as to be readable by every person whose calling or interests are in any way connected with or dependent upon the stock-raising industries of the Colony.

The publications of the Bureau of Agriculture in the United States have been freely consulted, and also information that has already been publisbed by the enthusiastic and keen investigators of Queensland.

In placing this matter before the public, it is not in any way desired to anticipate the publication of the conclusions arrived at and observations made by Messrs. Pound, Hunt, and Gordon in the northern Colony. All these gentlemen deserve the approbation of Australia for the capable, practical, and scientific way in which they have tackled this complicated problem, and I am anxiously looking forward to the publication of their experience and the scientific and practical results adduced, which I anticipate will materially add to the knowledge of the physiology of this disease.

Where in extracts from the writings of various investigators acknow. ledged as far as practicable throughout the text-technical phrases and terms have been altered into every-day parlance, I trust that the authors interested will forgive the liberty taken."

My thanks are due to Messrs. C. J. Pound, F.R.M.S., Director, Stock Institute, Queensland, and to E. Stanley, F.R.C.V.S., Government Veterinarian, New South Wales, whilst all credit is due to our respected Chief Inspector of Stock, Mr. Alexander Bruce, who has given substantial aid and advice.

Introduction. “Bovine tick fever" is the popular name proposed in place of the purely local title " Texas fever," by which this disease is known in America, and which has no bearing whatever upon either its cause or nature.

The designation " Bovine tick fever" was selected with due regard to both the cause and nature of the complaint which, judging from the results of many experiments, may be summed up in the two following important facts :=1. That the disease is purely bovine ; that is, it is confined to cattle, other animals such as horses, sheep, goats, pigs, rabbits, mice, guinea-pigs, &c., having been proved to be unsusceptible even when inoculated with diseased blood. 2. That the disease is naturally transmitted by the cattle tick (Ixodes bovis), and, so far as we at present know, by this means alone.

One has only to be seized with the latter fact, and accept the dictum, “No ticks, no fever !" to realise that a knowledge of the particular species of tick which carries the disease is essential to 'a complete understanding of so complicated a trouble.

In the following pages the cattle tick (Ixodes bovis), its habits and lifehistory, will be considered first, and at some length. Before doing so, however, I propose, at the risk of being considered tedious, to discuss ticks in their relationship to other animals—not, of course, as parasites, but as a branch of the great animal kingdom.

Students of the structure, habits, and relationships of animal to animal are known as zoologists, and the sorting out or arranging of animals together into natural groups is called " zoological classification." There are two kinds of classification in the ordinary sense of the term-an artificial classification and a natural classification.

These may be illustrated by books. For example, we are given a large number of books and asked to classify them. If we do so artificially we can arrange them by their size, their colour, or their binding. Of such a classification what would be the possible results ? A volume of Spurgeon's sermons sandwiched in between the work of a Huxley and a Byron. In a natural classification things would be quite different. Historical works would be found together, poetical works would be found together, and so on. This classification would even go further, for the historical works of France would be sorted by themselves and not jumbled together with those of England and Germany.

It will be seen that a “natural classification” entails a knowledge of the contents of the books being dealt with ; in fact, a "a looking into” of their natures.

So with the classification of animals. Where could we get a better illustration than a whale. At first sight we would classify a whale as a fish, but this is not the case. The whale is adapted for living in the water, and a study or "looking into" of its pature places it amongst such animals as cows, horses, &c., a branch of the animal kingdom (mammalia), of which man himself is the head.

The differences between a whale and a fish are these : The fish is a coldblooded creature and breathes through gills; the whale has warın blood, and, as most of us are aware, has to come to the surface of the water periodically to breathe fresh air. Again, a fish is covered with scales, whilst a whale's clothing, although very scarce, is typical hair. And, lastly, a fish lays eggs, whilst a whale produces its young alive, and, moreover, suckles them.

Classification. Animals are first grouped in Sub-kingdoms, which are divided into Classes, these again into Orders, the orders into Families, the families into Genera, and the genera into Species.

Thus, for example, we have a large number of dogs exactly alike, such as the Newfoundlands. These constitute a Species.* Then we have the Aus

* It is now generally believed that the majority of the numerous “breeds” of domestic dogs are varieties, all descended from a common ancestor-probably a domesticated wolf.

« AnteriorContinuar »