90 THE GOLDFISH AND ITS CULTURE. 



They all fly very rapidly, feed upon insects of every description 

 that they catch flying about, and from this fact they may be made 

 useful to destroy the mosquitoes in bedrooms and elsewhere. Al- 

 though very voracious, they are perfectly harmless to man they 

 can not injure him in any way. The manner of their copulation is 

 somewhat curious. The male fastens the extreme back part of its 

 body to the neck of the female, and thus attached, both fly 'about for 

 one or two hours, when, over some water, they separate. The 

 female then deposits her small white eggs by immersing the posterior 

 part of the body in the water, attaching them to the submerged 

 surfaces of water-plants; there they remain until hatched. 



The larvae or grubs of the dragon-flies live in the water; those 

 of the libellula are short and thick, while those of the other genera 

 are more slender, corresponding with the shape of the adult. The 

 color of these grubs varies from blackish-brown to a brilliant green. 

 They breathe through the posterior part of the body, which apparatus 

 is also used to propel them forwards through the water, making them 

 good swimmers. 



They are extremely destructive to young fish and fish-eggs, upon 

 which, together with tadpoles and snails, they manage to make a 

 good living. Instead of hunting their victims, they lay concealed in 

 the mud with the eyes only protruding from the surface. Whenever 

 a victim comes within reach, they produce their concealed pincers 

 by a rapid motion, rarely missing the mark they aim at. (See 

 illustration.) 



There are instances on record where one of the larvae of the 

 libellulae, which was overlooked in the fish-tank, destroyed two 

 thousand (2,000) young fish in a week's time. 



After they have attained their full growth, the grubs leave the 

 water, climb upon some object projecting from it, when the perfect 



