Dragon-flies and Damsel-flies 93 



water. The nymphs are slender, clean creatures, with smooth bodies pat- 

 terned with green and brown, and very active, strong, and brave. They 

 climb among green plants and roots or submerged driftwood along the border 

 of open water or the edge of a current. The imagoes of this family can be 

 recognized by the meeting of the eyes all along the top of the head. The 

 wings are long, broad, and clear, and the body-colors are mostly bright blue 

 and green. The family is represented in the United States by about twenty-five 

 species, belonging to six genera. Anax junius, one of the commonest dragon- 

 flies all over the United States, and found also from Alaska to Costa Rica, 

 in China, Siberia, and in various islands of the Pacific, notably the Hawaiian 

 group, is the most inveterate enemy that the mosquito has. It is conspicu- 

 ously on the wing from early spring to 

 late fall, flying from daylight to dark, 

 and doing untold good by its ceaseless 

 warfare on the mosquito hosts. It 

 can be recognized by its clear wings, 



large size (wings over two inches long), 



j , . , , , , , , FIG. i24a. FIG. 1246. 



and bright-green thorax and head, the 



latter bearing on the upper front a "Ha^Mta 



round black spot surrounded by yellow, junius. (Enlarged.) 



the yellow encircled by a dark-blue FIG. 1 24*. -Top of head showing charac- 

 J tenstic mark in front of eyes, of dLschna 



ring (Fig. 1240). A still larger member constricta. (Enlarged.) 



of this family is the great "hero" 



dragon-fly, Epiaschna heros, which is like Anax junius in general appear- 

 ance, but has wings two and one-half inches long, and abdomen nearly three 

 inches long. It has a black T spot on the upper face, instead of a round 

 one. Another similar, widely distributed and common form is dLschna 

 constricta, about the size of Anax junius, reddish brown marked with bright 

 green, and with a black T spot on the upper front of face (Fig. 1246). The 

 males have the abdomen marked with blue, with little or no green, while 

 the females have but little blue or none at all. 



The members of the family Libellulidae are called "skimmers." They 

 may be seen continually hovering over the surface of still water, or swiftly 

 foraging over fields. Many of them have the wings strongly marked with 

 large black or brown or milk-white blotches, and the abdomen is often 

 covered with a whitish powder or "bloom." They outnumber all the other 

 true dragon-flies in point of species, and except for Anax junius, JEschna 

 constricta, and perhaps the giant hero dragon-fly, include the most familiar 

 and wide-spread members of the order. One of the best known and most 

 beautiful of the skimmers is the pond-loving "ten-spot," Libellula pulchella 

 (Fig. 125), found all over the country. Each of its wings has a longitudinal 

 basal blotch, a median blotch (at the nodus), and an apical blotch of black- 



