DRAGONFUES AND DAMSEI^FUES IN PONDFISH CUIvTURE. 



251 



NASIi^ESCHNA PENTACANTHA (Rambur). 



Aeschna pentacantha Rambur, Ins. Netir., 1842, p. 208. 



This species is said to have a wide geographical range, but not to occur anywhere in abundance. 

 It was found quite plentifully around Patterson Lake and the slew leading up to it from the river. 

 Its habits are like those of other ^schnines; it patrols the banks, flying back and forth over a limited 

 area and frequently alighting and clinging to the underside of twigs and branches, its body hanging 

 vertically and its wings drooping. In this position it is not very difficult to catch. No old nymphs 

 or nymph skins could be found, although careful and continued search was made for them, but newly 

 hatched nymphs were obtained in August, 191 7. 



ANAX JUNIUS (Drury). 



Libellula junia Drury, lUust. Exot. Entomol., vol. i, 1773, p. 112. 



According to Kellicott, this species is the first to appear in the spring and almost the last to dis- 

 appear in the fall. During June the imagos were not very plentiful around the ponds,, but they increased 

 greatly in actual numbers and still more in relative abundance as the season advanced, and by the last 

 of August they were surpassed only by Lihellu la luctuosa. This is one of the most powerful fliers and almost 

 never alights except for ovipositing. At such times the two sexes fly about together and, alighting 

 upon some water plant at or near the surface of the water, the male assists the female as she inserts her 

 eggs in the tissue of the plant stem. Both sexes often have a regular beat which they patrol back and 

 forth for a long time; they also fly later at night than any other species, sometimes high in the air, catch- 

 ing the numerous small insects which they find there. 



Nymphs were found in all the ponds, but especially in 4 and 9, where they were not much dis- 

 turbed by the fish. This nymph is probably better known and more often figured than that of any other 

 dragonfly. It shows a great variety in its color pattern at different ages, as well as the usual differences 

 according to the nearness of the next molt. When very small, it is a uniform greyish green; as it grows 

 larger it becomes banded transversely with black and white, while the mature nymphs are bright grass- 

 green, with a beautiful and intricate color pattern of cinnamon brown. Two medium-sized nymphs 

 were taken in pond 4 that were snow white throughout and so transparent that the dark breathing 

 tracheae around the posterior intestine showed through plainly. 



The nymphs are most abimdant in waters filled with vegetation, and may be found even in small 

 ditches and pools, and there are sometimes two broods in a year. They expel the water from their 

 rectum with a noise like that made in ejecting saliva, and such spitting served to locate most of them 

 in pond 4 when the water was drawn. When those that were left in this pond transformed, they seemed 

 to find the screen across the outlet peculiarly attractive, and it was covered with bunches of skins. 

 Two of these bunches are shown in Plate LXVIII, figure i, the right-hand one containing six skins 

 in a row, each fastened to the one in front of it. 



i^SCNHA CONSTRICTA Say. 



i^lschna constricta Say, Jour. Acad. Nat. Sci., Phila., vol. 8, 1839, p. 11. 



Nymphs were found in all the ponds associated with those of Anax; they do not transform until mid- 

 summer or later, and hence no imagos are seen until then. The imagos frequently enter houses or 

 other buildings and may often be captured there. They wander afar in the fields and are seldom seen 

 around the ponds, preferring some small brook among the hills. They feed on flies as well as mos- 

 quitoes and often catch house flies and stable flies around our dwellings. 



MACROMIA Ti^lNIOLATA Rambur. 



Macromia taeniolata Rambur, Ins. Neur., 1842, p. 139. 



This and the following species were only foimd in the slews along the Mississippi River. None 

 have ever been seen around the fishponds, nor have any nymphs or nymph skins been found there. 

 Patterson Lake is a favorite resort of the imagos, but careful search in its waters failed to reveal any 

 nymphs. 



