The Insect World. Figuier Louis

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СКАЧАТЬ whose general organisation we have briefly traced, have been classed by naturalists as follows:—

      1. Aptera (Fleas and Lice).

       2. Diptera (Gnats, Flies, &c.)

       3. Hemiptera (Bugs, &c.)

       4. Lepidoptera (Butterflies and Moths).

       5. Orthoptera (Grasshoppers, Crickets, Cockroaches, &c.)

       6. Hymenoptera (Bees, Wasps, &c.)

       7. Thysanoptera (Thrips cerealium). 8. Neuroptera (Libellula, or Dragon-fly; Ephemera, or May-fly; Phryganea, or Alder-fly). 9. Coleoptera (Beetles).

      We shall commence the history of the various orders by examining the Aptera.

      I.

      APTERA.

      Insects of this order are without wings, and the name is derived from two Greek words, α, privative, and πτερον, wing, indicating the negative character which constitutes this order. [9] It consists of Fleas and Lice. The Flea (Pulex), of which De Geer formed a separate group, and called Suctoria, includes several species.

      The common flea (Pulex irritans, Fig. 17) has a body of oval form, somewhat flattened, covered with a rather hard horny skin of a brilliant chestnut brown colour. It is the breaking of this hard skin which produces the little crack which is heard when, after a successful hunt, one has the happiness to crush one of these parasites between one's nails.

Fig. 17. Flea (Pulex irritans).

      Its head, small in proportion to the body, is compressed, and carries two small antennæ, of cylindrical form, composed of four joints, which the animal shakes continually when in motion, but which it lowers and rests in front of its head when in a state of repose. The eyes are simple, large, and round. The beak is composed of an exterior jointed sheath, having inside it a tube, and carrying underneath two long sharp lancets, with cutting and saw-like edges. It is with this instrument that the flea pierces the skin, irritates it, and causes the blood on which it lives to flow.

      This bite, as every one knows, is easily recognised by the presence of small darkish red spots, surrounded by a circle of a paler colour. The quantity of blood absorbed by this little creature is enormous, when compared with its size.

      The body of the flea is divided into thirteen segments, of which one forms the head; three the thorax, which is short, and the remainder the abdomen.

      The limbs are long, strong, and spiny. The tarsus, or foot, has five joints, and terminates in hooks turned in opposite directions. The two anterior limbs are separated from the others, and are inserted nearly under the head; the posterior ones are particularly large and strong.

      The jumps which fleas are able to make are really gigantic, and the strength of these little animals quite herculean, when compared with the size of their bodies. The reader may be inclined to smile at the assertion that the flea possesses herculean strength; but let him wait a little, and he will find that it is no exaggeration.

      To give some idea of the strength, the docility, and the goodwill of the fleas, some wonderful little things have been made, which have served at the same time to show the astonishing skill of certain workmen.

      In his "Histoire abrégée des Insectes," published in the seventh year of the French Republic, Geoffroy relates that a certain Mark, an Englishman, had succeeded, by dint of patience and art, in making a gold chain the length of a finger, with a padlock and a key to fasten it, not exceeding a single grain in weight. A flea attached to the chain pulled it easily. The same learned writer relates a still more surprising fact. An English workman constructed a carriage and six horses of ivory. The coachman was on the box, with a dog between his legs, there were also a postillion, four persons in the carriage, and two servants behind, and the whole of this was drawn by one flea.

      In his "Histoire Naturelle des Insectes Aptères," Baron Walckenaer relates the following marvellous instance of industry, patience, and dexterity:—

      "I think it is about fifteen years ago, that the whole population of Paris could see the following wonders exhibited on the Place de la Bourse for sixty centimes. They were the learned fleas. I have seen and examined them with entomological eyes, assisted by a glass.

      "Thirty fleas went through military exercise, and stood upon their hind legs, armed with pikes, formed of very small splinters of wood.

      "Two fleas were harnessed to and drew a golden carriage with four wheels and a postillion. A third flea was seated on the coach-box, and held a splinter of wood for a whip. Two other fleas drew a cannon on its carriage; this little trinket was admirably finished, not a screw or a nut was wanting. These and other wonders were performed on polished glass. The flea-horses were fastened by a gold chain attached to the thighs of their hind legs, which I was told was never taken off. They had lived thus for two years and a half, not one having died during the period. To be fed, they were placed on a man's arm, which they sucked. When they were unwilling to draw the cannon or the carriage, the man took a burning coal, and on it being moved about near them, they were at once roused, and recommenced the performances."

      The learned fleas were the admiration and amazement of Paris, Lyons, and the chief provincial towns of France, in 1825.

      But how, one will ask, was it possible in a large public room to see this wonderful sight? And it is necessary that this should be explained. The spectators were seated in front of a curtain, provided with magnifying glasses, through which they looked, as they would at a diorama of landscapes or buildings.

      But let us return to the natural history of our insect. The female flea lays from eight to twelve eggs, which are of oval shape, smooth, viscous, and white.

      Contrary to what one might think, à priori, the flea does not fix its eggs to the skin of its victims. She lets them drop on the ground, between the boards of floors, or old furniture, and among dirty linen and rubbish.

      M. Defrance has remarked that there are always found mixed with the eggs a certain number of grains of a brilliant black colour, which are simply dried blood. This is a provision which the foreseeing mother has prepared at our expense to nourish her young offspring.

      In four or five days in summer, and in eleven days in winter, one may see coming out of these eggs small, elongated larvæ, of cylindrical form, covered with hair, and divided into three parts, the last provided with two small hooks. The head is scaly above, has two small antennæ, and is without eyes. These larvæ are without limbs, but they can twist about, roll themselves over and over, and even advance pretty fast by raising their heads. Though at first white, they become afterwards of a reddish colour.

      About a fortnight after they are hatched they cease to eat, and are immovable, as if about to die. They then commence to make a small, whitish, silky cocoon, in which they are transformed into pupæ. In another fortnight these pupæ become perfect insects.

      

      A most remarkable trait, and unique among insects, has been observed in the flea. The mother disgorges into the mouths of the larvæ the blood with which she is filled.

      The flea is most abundant in Europe and the North of Africa. Certain circumstances particularly favour its multiplication; being most abundant in dirty houses, СКАЧАТЬ