OF THE UNITED STATES 



47 



Uhler, a very close observer and competent entomologist, has 

 noticed that Libellula "alights upon water plants, and, pushing 

 the end of her body below the surface of the water, glues a bunch 

 of eggs to the submerged stem or leaf." 



These eggs are usually small and of a yellow color, while in 

 some of the Agrions they are of a bright pea green, and our Eng- 

 lish students observe that in this group the females have been 

 known to go down several inches beneath the surface of the 

 water, to deposit their eggs upon the stems of the plants. 



When summer is well advanced the eggs soon hatch, and then 

 the larva of various species of Dragon-flies are easily to be ob- 

 tained with an ordinary dip-net in any of our ponds or ditches. 

 They are very active aquatic insects with six legs, big eyes, large 

 head, and powerful jaws concealed by a facial mask. Constantly 

 feeding upon the larvae of mosquitoes and other noxious insects, 

 they perforin a. service of untold good, a career the matured flies 

 carry on in the air ever afterward until the day of their death. 

 In fact, of all the insects known to me, none can in any way 

 compare, in the matter of the amount of good done through the 

 constant destruction of harmful insects, with dragon-flies of 

 every species and kind. So far as man is concerned, the entire 

 life of any one of these insects is one of beneficence of the mor 

 pronounced character. 



In speaking of the larvae, Packard, our distinguished entomolo- 

 gist, has said: "Not only does the immature Dragon-fly walk over 

 the bottom of the pool or stream it inhabits, but it can also leap 

 for a considerable distance, and by a most curious contrivance. 

 By a syringe-like apparatus lodged in the end of the body, it dis- 

 charges a stream of water for a distance of two or three inches 

 behind it, thus propelling the insect forward. This apparatus 

 combines the functions of locomotion and respiration. Thert 

 are, as usual, two breathing pores (stigmata) on each side of the 

 thorax. But the process of breathing seems to be mostly carried 

 on in the tail.'' 



Perhaps the best way of all to study these insects, from this 

 time on. is to place a lot of them in a good-sized aquarium, in 

 which some small reed-like grasses and lilies have been made to 

 grow. This I have done many times as a boy, and what I then 

 saw has never been forgotten, nor the lesson lost. Here we may 

 observe how the larva of the Dragon-fly passes into the pupa 

 stage, the latter differing but very little from the former in ap- 



