92 Dragon-flies and Damsel-flies 



The family Cordulegasteridae includes only seven species of dragon-flies 

 found in the United States, all belonging to one genus, Cordulegaster. They 

 are large, with eyes barely touching on top of the head, without metallic 

 body-colors, and with clear wings. The nymphs burrow into the sand or 

 vegetable silt on the bottom of shallow places. Thus buried, with only 

 the top of the eyes and tip of the abdomen showing, they remain motionless 

 for a long time, if prey does not come near. "In a dish of sand on my table," 

 says Needham, "I have had a nymph remain without change of position 

 for weeks, no food being offered it. Let any little insect walk or swim near 

 the nymph's head, and a hidden labium springs from the sand with a mighty 

 sweep and clutches it." The imagoes are strong flyers and have the habit 

 of flying back and forth, as on a regular beat, over some small, clear stream. 



The family Gomphidas includes six genera, comprising about fifty species 

 in our country. They are mostly large forms, clear- winged and with bodies 

 striped with black and green or yellow. They are readily distinguished 

 by the wide separation of the rather small eyes. The abdomen is stiff and 

 spike-like. The eggs, held in a scanty envelope of gelatin, are deposited 

 by the repeated descent of the flying female to the water of a clear pond 

 or flowing stream, the tip of the abdomen first striking the surface. The 

 gelatin dissolves and the eggs, scattering, sink to the bottom and become 

 hidden in the silt. The nymphs are active burrowers, capturing their prey 

 either on or beneath the surface of the bottom silt. The adults often alight 

 on foliage, or on the surface of some log stretching across a stream, or on 

 the bare soil of a path or roadway. They do not fly about in apparent 

 sportiveness as the skimmers (Libellulidae, p. 95) do, nor, like the skim- 

 mers, perch atop a slender twig. June is the best month in the East for 

 these dragon-flies. The principal genus of the family is Gomphus, which 

 includes one-third of all our Gomphidae. Of these Gomphus exilis is 

 probably the most common one in the Northeastern States. Its head is pale 

 green, thorax brownish with two oblique green bands on each side, and 

 abdomen blackish brown with . a basal green spot or band on the back 

 of each segment. The nymphs transform at the very edge of the water ? 

 seldom crawling more than an inch or two above it. Hagenius brevistylus 

 is a large black-and-yellow species common in the East, South, and Middle 

 West. The nymph has an unusually wide, flattened body. 



The ^Eschnidae include our largest, swiftest, and most voracious dragon- 

 flies. Various species are flying through the whole season from early spring 

 to late summer. Some roam far from water, being found over dry fields 

 and roadways, and even in houses. Some forms fly until late in the even- 

 ing, making life a burden for the mosquitoes gathering for their night's 

 singing and feasting. The eggs are thrust into the stems of aquatic plants, 

 in floating timbers, in the wood of piers, etc., at or near the surface of the 



