CHAPTER XIII. 

 ODONATA. 



This is the order of the dragon flies and the damsel 

 flies, the fiercest of all predaceous insects, preying upon 

 other weaker insects, and upon the weaker members of 

 their own kind in the larval stage ; and even in the adult 

 stage the weaker occasionally furnish a meal for the 

 stronger. The damsel flies are the narrow-winged dragon 

 flies, and are more nearly strictly aquatic, usually flying 

 only short distances above the pond or river and not 

 making long excursions away from the vicinity of their 

 water haunts. Dragon flies fly higher over the water 

 surface, or into fields and sunny places generally; a few 

 species have a liking for the neighborhood of dwellings. 



All dragon flies have four strong wings, and the pairs 

 are nearly alike in size. The body is slender, smooth, 

 and cylindrical or tapering. Their flight is strong and 

 long-sustained, and the wings are built to stand this 

 strain. The subcostal vein of each front wing is placed 

 at the bottom of a groove, and the short cross- veins in that 

 groove are enlarged vertically so as to form effective 

 braces. About two-thirds of the way out to the tip of the 

 wing, there is a notch or node in the front margin of the 

 wing; and at or near this notch, there is usually a dark 

 spot called the pterostigma or wing mark. In some of 

 the species the wings are clear of other markings, but in 

 other species the wings are crossed by various bands or 

 spots of color. In the male of the Black Wing, the dark 



207 



