32 THE CANADIAN ENTOMOLOGIST. 



All of the Odonata deposit their eggs in water, and the young insects 

 bear some resemblance to the adults in the shape of the head and size of 

 the eyes, and in the avidity with which they prey upon other weaker insects. 

 The young of the Damsel-flies are more slender than those of the true 

 Dragon-flies and are further distinguished by having several flat leaf-like 

 plates at the hind end of the abdomen,which aid in purifying the blood by 

 acquiring fresh air from the very minute bubbles which are present in the 

 water. In the young of the true Dragon-flies there are no such plates, but 

 the air is drawn into and forced out of the hinder part of the body. 



There is, among the ignorant, much needless fear of the Dragon-flies. 

 In various sections they are known as Dragon-flies,Darning-needies, Snake- 

 doctors, Mule-killers, Mosquito-hawks, etc. Of these names, the fiist and 

 last give the truest idea of their habits. They are true dragons of the air, 

 and undoubtedly do devour immense numbers of mosquitoes; for woe 

 unto the gnat or small fly which is spied by a dragon-fly ! — a swift swoop 

 of the long, strong wings, a quick dart of the Dragon-fly, and the place which 

 knew the gnat knows it no more. They are absolutely harmless to man 

 and may be handled in the fingers with impunity : a slight pinching with 

 their jaws is all that they can give, — but this, while nothing to us, means 

 death to weaker creatures. 



The appetite of an adult Dragonfly is something remarkable. I have 

 seen specim.ens held in the hand cease struggling to munch on a proffered 

 fly, and the same thing may be observed even when the creature is impaled 

 on a pin which is passed directly through the body between the wings. 

 But most remarkable of all was the case in which a captured specimen, 

 when its own body was bent under so that the tip was near its mouth, 

 seized its own abdomen and ate off two of the segments 1 



The Odonata is a good example of a group of insects which for along 

 time were regarded as of no economic importance, but which suddenly 

 acquired interest. When it had been clearly demonstrated that mosquitoes 

 may transmit the germs of malaria and yellow fever to man, the question 

 of natural enemies of mosquitoes became important. Moscjuitoes lay their 

 eggs in water and the young are known as *■ wrigglers " or " wiggle-tails." 

 Coursing over the pool and marshes, the large, swift Dragon-flies surely 

 destroy many an impregnated female mosquito, or more likely destroy 

 them when they first emerge, before they are ready to lay eggs. In the 

 pool, creeping about on the bottom in the shallow places, the young Dragon- 

 fly doubtless makes many a happy meal on the luckless wrigglers which 

 come within reach. 



