The Living Animals of the World, Volume II: Birds, Reptiles and Amphibians, Fishes, Jointed Animals, Molluscs, etc.

Twowinged Insects 731

r its rain-water butt. The females of some species construct small rafts of eggs, which float about on the surface of the water till hatched, and then produce small maggots with a breathing-apparatus at the end of the tail. In this condition they swim head-downwards, while the more compact pupa floats head-upwards. They may be destroyed by pouring a little kerosene into their breeding-places; and as this floats on the surface of the water, it does not interfere with the use of the water in water-butts, which is usually drawn off by a tap below. The males of gnats often have feathered antennae and long, slender legs. The females, however, are

HORNET ROBBER-FLY. more nocturnal in their habits, and come into houses in the and keep people awake by their humming and pain- Common in the south of England. evening, ful "bites," or rather punctures, which frequently cause a is worse is that they are nowdistressing irritation for a day or two afterwards. What known to disseminate various diseases, such as elephantiasis and also malarial fever of every kind, in this manner from the comparatively mild ague of the English fens (now nearly extinct) to the terrible malaria of Southern Europe, India, and Africa, formerly attributed to the unhealthy atmosphere of marshy countries, or to exposure to the night air in warm countries, but now known to be caused by the bites of the gnats, or mosquitoes, which breed is believed that only certain species ofin swampy places, and fly about in the evening. It gnats convey the germs of these diseases; and it has been stated that, though ague-bearing species of gnats are still found in England, those which have been examined for the purpose have been free from these germs, and are therefore incapable of propa-gating the disease.

In many parts of the world gnats are excessively numerous and troublesome at certain seasons of the year, filling the air like clouds of dust, so that it is difficult to sleep or eat from the annoyance and irritation caused by their attacks. This will be readily credible to those who have experienced the pain which they cause even when not very numerous, and have been kept awake at night by their shrill piping as they approach. They appear to be equally numerous in cold and warm countries Lapland, France, South Eussia, Italy, various parts of America, and in fact most parts of the world being liable to the inordinate multiplication of different species.

In England they were formerly so abundant in the fenlands that mosquito-curtains were in use less than a century ago, and may be so still. But their numbers have so diminished of late years that, when- ~ ever gnats are a little more troublesome pkotobyw. P. Dando~F.Z.S.} (Regent' Park. than usual, it is reported that there has DADDY-LONG-LEGS. been an invasion Of mosquitoes. A year Or Large species, with variegated wings.

the World732 The Living Animals of

two ago there was a report that "mosquitoes" had been brought to Cromer in some fishing- " "vessel, and the newspapers contained paragraphs about mosquitoes having caused much annoyance in different parts of London. But many of the specimens submitted to the inspection of entomologists proved to be nothing more than the commonest of all the blood-sucking is producedgnats, called the PIPING-GNAT by Linnaeus, on account of its shrill note. The note by the rapid vibration of the wings, which has been estimated at the rate of 3,000 per minute. Gnats do not always fly near the ground. Sometimes they have been seen ascending from cathedrals and other high buildings in such vast swarms that they resembled clouds of smoke, and gave rise to the idea that the building was actually on fire.

Equally troublesome and annoying are the SAND-FLIES, as they are called in England, or the BLACK-FLIES, as they are called in America. They are very small flies, short and broad, and with broader wings than gnats; and one of them, which actually destroys many mules isand other domestic animals in the Mississippi Valley, as we learn from Professor Comstock, called the BUFFALO-GNAT, from a fancied resemblance of the side-view of the insect to a buffalo. Other species are equally destructive to the cattle in the Banat of Hungary. It is a 'curious circumstance that, in the case of nearly all two-winged flies which attack men and animals, it is usually only the females which suck blood, the males frequenting flowers and being perfectly harmless. Kespecting mosquitoes in South America, Mr. H. W. Bates writes, in his work " The Naturalist on the \ At Amazons," when passing a night in a ^^^^fL^^^ boat about twenty-five miles from the it town of Villa Nova: "At night quite impossible to sleep for mos- /C^P)\ ^X was f \ quitoes; they fell upon us by myriads, and without much piping came straight at our faces as thick as rain-drops in pkoto^y w.p.Dando, F.z.si wgtnc, Par*. a shower. The men crowded into the cabins, and then tried to expel the pests by the smoke from burnt rags; but it was of little avail, although we were half suffocated during the operation.”

HOVER-FLY. This fly has a superficial resemblance to a bee. (See page 734.)

RAT-TAILED LARVA. Common in filthy water.

But the sand-flies, encountered a little higher up the river, were much worse: " We made acquaintance on this coast with a new insect-pest, the Pium, a minute fly, two-thirds of a line in length, which here commences its reign, and continues henceforward as a terrible scourge along the upper river, or Solimoens, to the end of the navigation on the Amazons. It comes forth only by day, relieving the mosquito at sunrise with the greatest punctuality, and occurs only near the muddy shores of the stream, not one ever being found in the shade of the forest. In places where it is abundant, it accompanies canoes in such dense swarms as to resemble thin clouds of smoke. It made its appearance in this way the first day after we crossed the river. Before I was aware of the presence of flies, I felt a slight itching on my neck, wrist, and ankles, and, on looking for the cause, saw a number of tiny objects, having a disgusting resemblance to lice, adhering to the skin. This was my first introduction to the much-talked-of Pium. On close examination, they are seen to be small two-winged insects, with dark-coloured body and pale legs and wings, the falllatter closed lengthwise over the back. They alight imperceptibly, and, squatting close, at once to work, stretching forward their tiny front legs, which are in constant motion, and seem to act as feelers, and then applying their short, broad snouts to the skin. Their abdomens soon become distended and red with blood, and then, their thirst satisfied, they soon ismove off, sometimes so stupefied with their potations that they can scarcely fly. No pain felt whilst they are at work, but they each leave a small circular raised spot on the skin, and a disagreeable irritation. The latter may be avoided in great measure by pressing out the

Twowinged Insects 733

blood which remains in the s-pot; but this is a troublesome task when one has several hundred punctures in the course of a day [like Prince Siror, in one of Bulwer five hundred Lytton's stories, who fell " pierced by spears"]. I took the trouble to dissect specimens, to ascertain the way in which the little pests operate. The mouth consists of a pair of thick fleshy lips, and two triangular horny lancets, answering to the upper lip and tongue of other insects. This is applied closely to the Photo by W. P. Dando, F.Z.S., Regent's Park. skin, a puncture is made with the lancets, and the blood HOUSE-FLY (MALE AND FEMALE). house-fly live in refuse, so do not thrivethen sucked through between these into the oesophagus, The larvse of the the circular spot which results coinciding with the where cleanliness abounds. shape of the lips. In the course of a few days the red spots dry up, and the skin in time becomes blackened with the endless number of discoloured punctures that are crowded together. The irritation they produce is more acutely felt by some persons than others. I once travelled with a middle-aged Portuguese who was laid up for three weeks from the attacks of Pium, his legs being swelled to an enormous size, and the punctures aggravated into spreading sores."

However, the traveller in Amazonia has one consolation: the great rivers which traverse the forests are of three different colours; and the black-water rivers so called from the dark colour of the water, owing apparently to the amount of vegetable matter which they hold in solution are never infested with mosquitoes. Probably the character of the water renders it unsuitable to them for breeding purposes.

The CRANE-FLIES, or DADDY-LONG-LEGS, are also very injurious insects, but in a different manner, for their subterranean maggots feed on and destroy the roots of grass in the same way as the grubs of the Cockchafers. They are insects of considerable size, with slender bodies, terminating in a short, horny point (the ovipositor) in the female, and with long, slender legs, which are liable to break off at the least touch. The commonest species has a grey body and transparent wings; but there is a larger one with the wings prettily variegated with brown, and a smaller one in which there are yellow markings towards the end of the body.

The more typical FLIES have usually shorter and broader wings, and thicker, shorter, and more hairy legs, than those just mentioned; and the antennae have usually only three or four joints, and are often furnished with a long, slender bristle at or before the end of the last joint.

As in the case of the Gnats and Crane-flies, so as regards the more typical Flies, we have only space to notice a few of the more important families.

Some of the (TAD-FLIES are no larger than house-flies, but others are as large as wasps or larger, with broader wings, and of a black, grey, or yellowish colour; they frequent fields, and settle on cattle, or on our clothes or hands. Some have transparent and others dark-coloured wings, but they are all capable of inflicting a severe puncture, often sufficient to draw blood, even in the case of the smaller species. The prettiest of the gad-flies are the GOLDEN-EYED FLIES. They are black, with the abdomen more or less marked with yellow; and black, or black and transparent, wings. The eyes are of a beautiful golden green, dotted and lined with purple. They are moderately stout insects, about the third of an inch long, and are not uncommon. Another insect, known as the BLOOD-SUCKING EAIN-FLY, has a rather long arid slender body for a gad-fly, and is nearly half an inch long. It is of a lighter or darker grey, with reddish markings on the sides of the abdomen in the male. The wings' are greyishJ brown withPhoto ly\l. P. Dando, F.Z.S., Regents Part.: whitish dots, and & white mark towards the tip. Both these BLUE-BOTTLE FLY, OK BLOW-FLY. These flies deposit their eggs on meat, when ' flies are veiT troublesome, the latter chiefly on the edges of it becomes "fly-biown." woods or near water, especially in rainy weather.