ODONATA. 209 



in the afternoon, on his way home, you will usually find 

 his mouth full of flies, so full that he has not yet had time 

 to stop to chew and swallow them. The prey is caught 

 by the six slender legs, and then held by the front, legs 

 while the insect devours it. 



It is a curious fact that, with the draining of the 

 ponds and streams for the extermination of the harmful 

 mosquitoes, has come a decrease in the number of dragon 

 flies. If these dragon flies ate only mosquitoes, this would 

 not be a serious matter ; but the large service which dragon 

 flies render in eating flies, gnats, and moths, puts another 

 face on the situation. For several years, since 1895, in 

 fact, there has been an organized crusade against mos- 

 quitoes, and it has been quite successful in ridding the land 

 of large numbers of these pests. But the house and the 

 stable flies constitute an even greater menace to the health 

 of human communities as well as to lower animals, and 

 chiefly because they are a tolerated nuisance; and for 

 that very reason, dangerous in the extreme. It would 

 seem, therefore, that the loss of any insects that prey 

 upon flies would be productive of an increase in disease 

 among human beings, unless direct measures were taken 

 against the breeding and domestic harboring of these 

 pests. Stock-breeders pay more attention to the attacks 

 of bot flies and horn flies than do human beings to the 

 insidious approach of the disease-carrying house and 

 stable fly in our homes, living-rooms, sleeping-rooms, and 

 dining-rooms. Whether this decrease in the number of 

 dragon flies will result in disturbing noticeably the balance 

 of nature remains to be seen. 



The development is with incomplete metamorphosis, 

 the larval stage being greatly extended and the pupal 

 stage lacking. The egg-laying is accomplished usually 



14 



