732 The Living Animals of the World 



two acTo there was a report that " mosquitoes " had been brought to Cromer in some fisliing- 

 vesseir and the newspapers contained paragraphs aljout " 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-suckmg 

 gnats, called the Pifing-unat by Linnwus, 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 \-ast 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 Comstoek, 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 jierfectly 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 tw'enty-five miles from the 

 town of Villa Nova : " At night it 

 was quite impossible to sleep for mos- 

 quitoes ; they feU upon us by myriads, 

 and without much pjiping came straight 

 at our faces as thick as rain-drops in 

 pi..-Ao,hsn:p.Du.,do.F.z.s.-\ [ii.,j..a-.p.,ri: a shower. The men crowded into the 



HOVER-PLY. RAT-TAILED LAKVA. cabius, aud then tricd to expel the 



This fly has a superficial resemUance to a bee. Common in filthy water. ^^^^^^ by the SUlokc from bumt 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 }ilaces 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 ax'oided in great measure by pressing out the 



