732 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 PiPlNG-GNAT by Linnaeus, 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. 



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 

 H at our faces as thick as rain-drops in 



Fn,t,, t, W. P. Band., f.Z.S. , . . . . , 



a shower. I he men crowded into the 

 HOVER-FLY RAT -TAILED LARVA ^^ and then tried tQ , the 



This fly has a superficial resemblance to a bee Common in filthy -water . r . 



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 Piiim, 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 Piiim. 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 



