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AQUATIC INSECTS IN NEW YORK STATE 225 



the base of each lateral lobe. Movable hook strong, arcuate. 

 Distal end of lateral lobe divided. 



Legs long, slender, smooth; no lateral carinae or spines on 

 the abdomen; wings reaching the middle of the fourth segment; 

 gills thick, with smooth and not very sharp carinae. 



In half grown specimens femora, tibiae and gills are often 

 distinctly triple banded with brown, and the median cleft of the 

 labium extends hardly below the level of the bases of the lat- 

 eral lobes. 



The females descend on stems of more or less completely sub- 

 merged aquatic plants (such as Elodea), and, unattended by the 

 males, insert their eggs thickly into the green stems, just below 

 the surface of the water. 



HETAERINA 



This genus includes some of the most beautiful of insects.. It 

 is abundantly represented in the tropical parts of America; but 

 for our State a single species is recorded. Another species 

 which occurs in Pennsylvania may yet be discovered within our 

 borders. 



The common northern species, H. americana [pi. 12], fre- 

 quents slow flowing streams. The images are on the wing in late 

 summer and early autumn, flitting about the borders of riffles. 

 The males are very showy, and are easily distinguished from all 

 our other dragon flies by the presence of a bright crimson streak 

 on the base of each wing. Though their flight seems rather 

 fluttering and uncertain, they are not very easy to capture when 

 at the hight of their activity: they dodge quickly, and fly across 

 stream frequently. Once, while collecting with a net of red 

 mosquito bar,, after trying vainly for half an hour to capture a 

 specimen where specimens were not scarce, I stopped in dis- 

 couragement with the net under my arm, the bag behind me, 

 and rested. A moment later, looking back over my shoulder, 

 I saw a fine male Hetaerina sitting on the edge of my net. Care- 

 fully disengaging the handle from my arm, I managed to sweep 

 him into the bag. Then I turned my attention to the others 

 that were fluttering about the stream, and found I could easily 

 accomplish by strategy what I had failed to do by force. There 

 were few good alighting places about the stream, and I found 



