DADDY-LONG-LEGS.
Large species, with variegated wings.
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 Russia, 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, whenever gnats are a little more troublesome than usual, it is reported that there has been an invasion of mosquitoes. A year or 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 gnats, called the Piping-Gnat by Linnæus, on account of its shrill note. The note is produced 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 and other domestic animals in the Mississippi Valley, as we learn from Professor Comstock, is 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.
Photos by W. P. Dando, F.Z.S.
HOVER-FLY.
This fly has a superficial resemblance to a bee. (See page [734].)
