WAYS OF THE WILD.

Auckland Star, Volume LXI, Issue 27, 1 February 1930, Page 1 (Supplement)

WAYS OF THE WILD.

A NATURALIST'S NOTEBOOK. mtAGOK ITJES. (By A. T. PYCROFT.) Mr. T. Scott, Long Drive, St. Helier's, has given me a dragon fly whose colour, size, and speed of flight attracted his attention. It hue a wing spread of two and three-quarter inches, and is a female, being distinguished from the male by a pair of slender sickle shaped hooks attached to the end of her body. It is a very powerful flyer and is found throughout New Zealand, being very common at the Chathams. Its rapid and continuous flight often takes it miles away from any water. The dragon flies form a very natural and distinct group of insects. All the species are recognised with ease as belonging to the family. They are invariably provided with wings in the perfect state, and many of them are amongst the most active of insects. Their anatomy is in several respects very remarkable. The head is large and ia concave behind. It it attached to the thorax in such a way that it rotates on two cervical calcarious projecting parts that project forwards, and in some cases almost meet in a point in front. Hence it possesses extreme mobility, the* power of rotation being very great. Enormous Eyes. The eyes are always large, in some cases they are even enormous, and occupy the larger part of the area of the head. The upper facets of the eye are in many cases larger thin the lower, and in a few forms the line of division is sharply marked transversely. There are three ocelli, or minute simple eyes, which, when the size of the compound eyes is not too great, are placed in the usual manner as a triangle on the top of the head. In the forms where the compound eyes are very large the portion of the head between is, as it were, puffed out so as to form a projection just in front of where the eyes meet, and one simple eye is then placed on each side of this projection. The third eye is placed in front of the projection we have mentioned, by which it is often much concealed. This eye is sometimes of unusually large size. This insect, no < doubt, received the name of dragon fly on account of its large head and enormous eyes having a fanciful resemblance to the fabulous winged monster of mythology. At one time the name "horse stinger" was given to i';hese insects, harmless as far as man and animals are concerned, because it waß believed they stung horses. As a matter of fact, they have no stings. Prey Upon Insects. In the highly modified forms of dragon flies, the parts of the mouth are very peculiar, especially the lower lip. The mouth in the smaller and less active species is less remarkable. Our dragon flies belong to a family which are carnivorous, their prey being living insects which are captured by the dragon fly on the wing. It is believed that the mouth is largely instrumental in the capture, though the flight of these insects is so excessively rapid that it is difficult, if not impossible, to verify the action of the mouth pieces by actual observation. For the purpose of securing the prey, a mouth that/:an change its capacity to a considerable extent and with rapidity is a desideration, and these qualities are present in the mouths of those dragon flies that capture their prey while hawking.. The upper lip is very mobile, is pendent, and closes the mouth above, while the lower lip entirely closes the under part by means of two mobile plates. The wings of the dragon flies are usually transparent and provided with a multitude of small meshes. The hind wings are about as large as the front pair, or even a little larger. The wings are always elongate in comparison to their breadth, and have no folds. The legs are slender and are chiefly remarkable for the beautiful series of hair-like spines with which they are armed, and which in some forms are of considerable length. It is believed that the legs are of great importance in capturing the prey. The position of the legs in relation to the other parts of the body is peculiar t<o the dragon flies. Tht legs seem to be unfit for walking, the insects never using them for that purpose. Young Pass Suddenly to Aerial Life. The eggs are deposited either in the water, or in the stem of some aquatic plant, the female occasionally undergoing submersion in order to accomplish the act. The young, on hatching, are destitute of any trace of wings, which are said to make their appearance only at the third or fourth moult. The number of moults which take place have not been observed, but they are believed to be numerous. The fact that the dragon fly passes suddenly, in the middle of its existence, from an aquatic to an aerial life makes the condition of its respiratory organs a subject for intensive inquiry. Notwithstanding their great powers of flight, dragon flies are destroyed by birds of various kinds. The number of insects killed by dragon flies in places where they are abundant must be enormous. The young, or nymphs, are very destructive in the water they inhabit, so that dragon flies have, no doubt, been no mean factor in maintaining that important and delica e balance of life which it is so difficult for us to appreciate. Appetite for Food Insatiable. The dragon flies must be ranked anion" the most highly organised insects °so far as external structure and powers of locomotion are concerntd. Their prev are captured by their own superior powers of flight. _ Tiiey destroy a sreat manv insects, their appetite for food being apparently almost insatiable. They are ordinarily constructed for the purposes of their predatory lives. They fiv with great swiftness and change the lirection of their flight with admirable facility. They are. however, dependent >n sunshine and conceal themselves in lull and cloudy weather. The large [ragon flies appear to have hawking [omains of their own. Places where >ther insects abound are naturally those nost frequented. They at one time nspired the rustics, who gave them the larne of "horse stingers," with some ort of fear. In North America they are ailed "devil's darning needles." The .version to dragon flies is due to their ppearance. The idea that they are langerous to anything but their insect ictims is entirely erroneous. They may >e captured and handled without their nflicting any injury.