184 DRAGONFLIES OF NORTH AMERICA 
on that genus.* He has found that they inhabit rather out of the way 
places in the wilder districts, preferring well aerated bogs in the uplands 
or near the sources of the cooler forest streams. The adults have a 
rather long life of a month and half or so, and are attracted by sunny 
sheltered spots in the woods, or edges of clearings and lumber roads. 
The tenerals of some species ‘‘commonly fly at a height of 30-50 feet 
or more and may be seen on sunny days traveling back and forth, but 
keeping as a rule within a quite limited area of only a few square yeards 
or so, for long periods.’’ When in search of prey they doubtless fly 
lower. The flight of the adult at breeding time is quite different. 
They fly low, within a few feet or less of the water or bog. The males often fly 
back and forth over a bog or pond or skirt the shore of a stream or lake, travelling 
in a series of rapid forward movements, alternating with periods in which they 
hover almost motionless, except for the rapid vibration of their wings. 
Dr. Walker notes two main methods of oviposition. The first is 
characteristic of those which have a backwardly directed scoop-shaped 
ovipositor. These fly low over the water and strike it, or the wet moss, 
with the end of their abdomen, liberating a large number of eggs at 
each stroke. They sometimes hover over one place for 2 or 3 seconds, 
tapping the water at intervals. Those in which the ovipositor projects 
downward and is pointed, strongly compressed and spout-shaped, 
always oviposit in flight, in the wet sand, mud or moss near the water’s 
edge, or in the stream bed. 
The Known Nymphs 


Species Length Lat. sp. Lat. sp. Dorsal hooks | Ment. | Lat. Described by 
of 8* of 9* set. set. 
albicincta 22 1/5 1/5 0 11-12 | 5-6 Walk. ’25, p. 170 
cingulata 27 1/6-1/5 1/5 0 10-13 | 6/7 Walk. ’25, p. 185 
elongata 23 1/7 1/6 4-9 11-12 | 6-7 Ndm. '03 p. 269 
forcipata 20 0 Oorr. 0 12-15 | 9-10 | Walk. ’25, p. 138 
franklini 18 0 x: 0 13 | 7-8 | Walk. ’25, p. 120 
hudsonica 24 1/12-1/9 | 1/10-1/6 0 10-14 | 7-8 | Walk. ’25, p. 179 
kennedyi 21 0 r. 0 12-13 9 Walk. ’25, p. 129 
linearis 22 1/5 1/4-1/5 mod. 5-9 11-12 8 Ndm. '03, p. 269 
r.on 4 
minor 22 1/4 1/3 high 4-9 11-13 | 6-8 | Walk. ’25, p. 65 
semicircularis 22 0 variable 0 10-13 Walk. ’25, p. 149 
tenebrosa 20 1/6 1/5 strong 6-9 11-12 8 Walk. ’25, p. 104 
r.on4&5 
whitehousi 21 0 0 0 9-10 | 6-8 Walk. ’25, p. 156 
williamsoni 24 1/5 1/4-1/3 low 5 or 11-12 8 Ndm. ’01, p. 500 
6-9 (as elongata) 

* As compared with length of segment bearing them. 
* The material incorporated under this genus has been taken almost exclu- 
sively from The North American Dragonflies of the Genus Somatochlora by E. M. 
Walker, University of Toronto Studies, Biological Series, No. 26. 1925. 
