AQUATIC INSECTS IN THE ADIRONDACKS 457 



from this state. It was common at Saranac Inn, and even more common, 

 judging by the numbers of exuviae in evidence along the bank, at Axton 

 along Stony brook. But few imagos were seen at large, but many were 

 bred from nymphs taken from Little Clear creek beside the hatchery. 



This species, unhke most Odonata, seems to prefer dayhght, and even 

 midday as a time for transformation. The boarded banks of the im- 

 pounded creek beside the hatchery were watched through the entire 

 season, and each day the exuviae left there were gathered. Rarely were 

 any fresh skins found there early in the morning. July was so rainy there 

 was comparatively Httle time suitable for transformation; and, when the 

 clouds would break away about noon and the sun shine out, I could be 

 sure, on going out, to find some nymphs in transformation. On the few 

 clear days, this was most often observed about noon. All the skins 

 observed were left 3-30 inches above the surface of the water. The 

 nymphs are rather slow and sprawHng. The imagos seem to spend 

 little time in flight, preferring to rest on timbers about the rapids of the 

 stream. 



Nymph. (PI. 18, fig. 2) Measures in total length 42 mm ; abdomen 

 28 mm; hind femur 5.2 mm; width of head 6.^ mm, of abdomen 8 mm. 



Body elongate, depressed, with the long abdomen regularly tapering 

 for half its length; the fringe of hairs on lateral margins very dense and 

 soft; color yellowish brown, darker on the sides of the thorax; eyes 

 black; ocelli yellowish; a double row of trapezoidal blackish spots on 

 the abdomen between the middorsal line and the line of scars each side, 

 each spot with a prolonged external apical angle reaching the apical 

 carina on each segment, the spots on segnnients 9 and 10 becoming 

 diffused over the sides of die segments ; a series of minute, longitudinal 

 yellowish dashes in the apical sutural area of each segment. That so 

 much of color pattern is observable is doubtless due to the fact that these 

 nymphs live in comparatively clean sand. 



Abdomen depressed, and with a well marked middorsal impressed 

 line, and no dorsal hooks, save the merest rudiment on the apex of the 

 ninth segment ; lateral spines well developed on segments 6-9 (there are 

 tufts of hairs on the latter apical angles of segments before the sixth) in- 

 creasing a little in size posteriorly, those of the ninth segment closely 

 appressed, and hardly surpassing the base of the tenth segment. 



Mentum of labium a third longer than wide; front border of median 

 lobe nearly straight, with a sparse fringe of flattened scale like hairs; 

 lateral lobe strongly mcurved at about a right angle beyond the base of 

 the movable hook; about four teeth on the inner margin, increasing a 

 httle in size posteriorly. 



While nymphs of several sizes were taken together in the creek, they 

 seemed to have a definite period, including hardly more than the month 

 of July, for transforming. 



Aug. 2 was the date of the first imago captured at large. June 30 

 was the date of the first imago bred. 



