334 THE LIVING ANIMALS OF THE WORLD 
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 Linnzus, 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. 
1 Respecting mosquitoes in South 
America, Mr. H. W. Bates writes, in 
his work “ The Naturalist on the 
Amazons,” when passing a night in a 
boat about twenty-five miles from the 
town of Villa Nova: “At night it 
was quite impossible to sleep for mos- 
quitoes; they fell upon us by myriads, 
and without much piping came straight 
at our faces as thick as rain-drops in 
ashower. 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.” 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 Pidm. On close examination, they 
are seen to be small two-winged insects, with dark-coloured body and pale legs and wings, the 
latter closed lengthwise over the back. They alight imperceptibly, and, squatting close, fall 
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 
move off, sometimes so stupefied with their potations that they can scarcely fly. No pain is 
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 
Photos by HW’. P. Dando, F.Z.S. 
HOVER-FLY RAT-TAILED LARVA 
This fly has a superficial resemb ance to a bee Common in filthy water 
(See page 734) 
