826 



A HISTORY OF 



small, that the extremity of it can scarcely 

 bediscerned through the best microscope that 

 can be procured. That part which is at 

 first obvious to the eye, is nothing but a long 

 scaly sheath under the throat. At near the 

 distance of two-thirds of it, there is an aper- 

 ture, through which the insect darts out four 

 stings, and afterwards retracts them. One of 

 which, however sharp and active it may be, 

 is no more than the case in which the other 

 three lie concealed, and run in a long groove. 

 The sides of these stings are sharpened like 

 two-edged swords; they are likewise barbed, 

 and have a vast number of cutting teeth to- 

 wards the point, which turns up like a hook, 

 and is fine beyond expression. When all 

 these darts are stuck into the flesh of animals, 

 sometimes one after another, and sometimes 

 all at once, the blood and humours of the ad- 

 jacent parts must unavoidably be extrava- 

 sated ; upon which a tumour must consequent- 

 ly ensue, the little orifice whereof is closed 

 up by the compression of the external air. 

 When the gnat, by the point of her case, 

 which she makes use of as a tongue, has 

 tasted any fruit, flesh, or juice, that she has 

 found out ; if it be a fluid, she sucks it up, 

 without playing her darts into it; but incase 

 she finds the least obstruction by any flesh 

 whatever, she exerts her strength, and pierces 

 through it, if possibly she can. After this 

 she draws back her stings into their sheath, 

 which she applies to the wound in order to 

 extract, as through a reed, the juices which 

 she finds enclosed. This is the implement 

 with which the gnat performs her work in the 

 summer, for during the winter she has no 

 manner of occasion for it. Then she ceases 

 to eat, and spends all that tedious season 

 either in quarries or in caverns, which she 

 abandons at the return of summer, and flies 

 about in search after some commodious ford, 

 or standing water, where she may produce 

 her progeny, which would be soon washed 

 away and lost, by the too rapid motion of any 

 running stream. The little brood are some- 

 times so numerous, that the very water is 

 tinged according to the colour of the species, 

 as, green, if they be green, and of a sanguine 

 hue, if they be red. 



These are circumstances sufficiently ex- 

 traordinary in the life of this little animal ; 



but it offers something still more curious in 

 the method of its propagation. However 

 similar insects of the gnat kind are in their 

 appearance, yet they differ widely from each 

 other in the manner in which they are brought 

 forth, for some are oviparous, and are pro- 

 duced from eggs; some are viviparous, and 

 come forth in their most perfect form; some are 

 males, and unite- with tin- female; some are fe- 

 males, requiringthe impregnation of the male; 

 someareof neithersex.yet still produceyoung, 

 without any copulation whatsoever. This is 

 one of the strangest discoveries in all natural 

 history ! A gnat separated from the rest of 

 its kind, and enclosed in a glass vessel, with 

 air sufficient to keep it alive, shall produce 

 young, which also, when separated from each 

 other, shall be the parents of a numerous 

 progeny. Thus, down for five or six genera- 

 tions, do these extraordinary animals propa- 

 gate without the use of copulation, without 

 any congress between the male and the fe- 

 male, but in the manner of vegetables, the 

 young bursting from the body of their parents, 

 without any previous impregnation. At the 

 sixth generation, however, their propagation 

 stops; the gnat no longer produces itslike, from 

 itself alone, but it requires the access of the 

 male to give it another succession of fecundity. 

 The gnat of Europe gives but little un- 

 easiness; it is sometimes heard to hum about 

 our beds at night, and keeps off" the ap- 

 proaches of sleep by the apprehension it 

 causes ; but it is very different in the ill- 

 peopled regions of America, where the wa- 

 ters stagnate, and the climate is warm, and 

 where they are produced in multitudes be- 

 yond expression. The whole air is there 

 filled with clouds of those famished insects, 

 and they are found of all sizes, from six in- 

 ches long to a minuteness that even requires 

 the microscope to have a distinct perception 

 of them. The warmth of the mid-day sun 

 is too powerful for their constitutions ; but 

 when the evening approaches, neither art 

 nor flight can shield the wretched inhabitants 

 from their attacks; though millions are de- 

 stroyed, still millions more succeed, and 

 produce unceasing torment. The native 

 Indians, who anoint their bodies with oil, 

 and v\ho have from their infancy been used 

 to their depredations, find them much les 



