68 PBACTIOAL OABP CULTURE. 



The wings of the first two named, are, when the insect is at rest, 

 always expanded horizontally, while those of the latter are folded to- 

 gether, pointing backward. 



The hind part of the body in all of them is long, slender, and com- 

 posed of ten rings. On the forepart of the body, they have three pairs of 

 legs, and two pairs of transparent, webbed wings, the latter in some 

 species glitter like gold, in others they are dotted with spots of different 

 color; in the Agrion species they are of the same color as the body. The 

 coloring of the bodies of all, especially the seshma, is very brilliant, being 

 of a bright green, blue or scarlet, and sometimes mottled and spotted 

 with various colors. 



The eyes are large and prominent, giving the insects a very large field 

 of vision. 



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. Although very vora- 

 cious, they are perfectly harmless to man they cannot 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 egjjs by 

 immersing the posterior part of the body in the water, attaching them too 

 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 libellulse, 

 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 fly makes 

 Its appearance through the back of the grub, rising upon its wings into 

 the air as soon as they are unfolded and dry. 



The eggs are also produced twice in a season, the grubs from the last 

 deposit, living in the mud during the winter, and produce in the early 

 spring the first dragon flies of the season. 



