252 



BUI.I.ETIN OK THE BUREAU OI^ FISHERIES. 



MACROMIA ILLINOIENSIS Walsh. 

 Macromia illinoiensis Walsh, Proc. Acad. Nat. Sci., Phila., 1862, p. 397. 



Like the preceding species this one is never found around the ponds, but may be seen frequently 

 along the river bank and at sunset in the cornfields flying back and forth between the rows. At night 

 both species congregate in favorite places upon low bushes and hang by their legs from the under side 

 of the branches like Nasiaeschna. 



EPICORDULIA PRINCEPS (Hagen). 



Epitheca princeps Hagen, Synop. Neuropt. of N. A., 1861, p. 134. 



This species is easily recognized by its large size, by the brown blotches on its wings at the nodus 

 and stigma, and by the fact that there are never any white areas connected with these blotches as in 

 L. pulchella. 



The males have regular areas which they patrol incessantly hour after hour, hawking the varied 

 insect life they may find. 



The nymphs are common in all the ponds; but the imagos scatter after emerging, and only a few 

 are seen about the ponds at any one time. The nymph is large and sprawling and can not cling well 

 to grass stems, preferring a broad surface like a board, a stump, or even the side of a bank. Most of 

 those taken at the ponds were found on a hard mud bank beside the cinder road. The two sexes do 

 not fasten together during oviposition, but the female drops her eggs alone into deep water. 



The imago emerges early in the morning and is one of those that consequently falls a prey to the 

 birds, since it is helpless during the first forenoon. Some of the wings of this species were foimd with 

 those of L. luciuosa already noted (p. 222). 



PANTALA FLAVESCENS (Fabricius). 



Libellula flavescens Frabricius, Entomol, System. Supple., 1798, p. 285. 



This species was found more plentifully upon the Illinois side of the river, but was occc^ionally 

 taken around the fishponds. Nymphs were found in ponds 4 and 8, and skins were obtained along 

 the shores of ponds 1,2, and 3. 



The imagos are rapid flyers and very difficult to Capture while on the wing; they congregate in 

 open places near the river bank, where they may be recognized by their reddish-yellow color and 

 strong flight. 



Apparently they never become really numerous anywhere in the vicinity of the station, but are 

 one of the rarer species. 



PANTALA HYMENi5:A (Say). 



Libellula hymenaea Say, Jour. Acad. Nat. Sci., Phila., 1839, p. 18. 



Similar to flavescens, but with a distinct fuscous spot at the base of the posterior wings; common 

 along the river bank just above the ponds in series B. Like flavescens they are rapid flyers and difficult 

 to capture while on the wing, but, unlike that species, they frequently alight upon the imder side of a 

 twig of some bush or tree like Macromia and Nasiaeschna, and can then be captured easily. 



Nymphs were taken in ponds 3 and 4, but no skins were found in any of the counts made. Neither 

 imagos nor nymphs occur in sufficient numbers to, affect the ecology of the ponds. 



TRAMEA LACERATA Hagen. 



Tramea lacerata Hagen, Synop. Neurop. N. A., 186 1, p. 145. 



This species can be readily recognized even when flying by the large black blotches at the bases 

 of the posterior wings. The male accompanies the female while ovipositing, and the two may fre- 

 quently be seen flying tandem over the ponds. Early in the season, June and the first of July, the 

 species is comparatively rare, but later they become more numerous and by the last of August they 

 share with Anax the honors of first place. Nymphs were found in all the ponds, and skins were 

 obtained in every count made, those in August being especially numerous. 



