The Gnat. 593 



larvae, which the eggs contain, escape into the water in 

 which they swim about with vigorous jerking move- 

 ments. They are compelled to visit the surface to take 

 in a supply of air, and for this purpose the tail is fur- 

 nished with a short tube, surrounded at its extremity with 

 a star of bristles, which, when spread out, prevent the 

 water from flowing into the air tube. The change to 

 the pupa state is a curious one. In this condition the 

 insect exhibits a rather slender body with a bulky an- 

 terior extremity, in which the head, wings, and limbs are 

 enclosed ; the tail is furnished with a pair of leaves or 

 membranous plates, the matting tube has vanished from 

 this part and in place of it we find two tubes situated on 

 the sides of the thorax : having passed about ten days in 

 this state, its increase being at an end, it keeps longer 

 near the surface, and at last the outer skin bursts, and 

 the winged insect, standing upon the exuvice it is going 

 to leave behind, smooths its new-born wings, springs 

 into the air, and begins its depredations. The fecundity 

 of the Gnat is so remarkable, that in the course of one 

 summer they might increase to the amazing number of 

 five or six hundred thousands, if Providence had not 

 ordered that they should become the prey of birds, who 

 by this means prevent their multiplying more than they 

 generally do. These insects are very annoying from their 

 blood-sucking propensities ; and as the sucker is horny 

 at the tip, it inflicts a severe wound, into which the insect 

 emits a small quantity of poison, which occasions the pain 

 and inflammation always felt from a Gnat bite. 



