90 PRELIMINARY NOTES ON THE ODONATA. 
SUB-ORDER ZYGOPTERA, THE DAMSEL-FLIES. 
FAMILY AGRIONIDAE. 
SUB-FAMILY CALOPTERYGINAE: 
Genus Calopteryx Leach. 
C. maculata Beauv. Wilson’s records of this widely distributed 
and usually common species are the only ones thus far for the State: 
Lake Amelia and Reed’s Landing, July 6 and 7, and 18, 1907. It is 
common to the Transition and Austral Zones and has been taken fre- 
quently in lowa and Wisconsin. 
This very conspicuous damsel-fly is to be found along streams, 
generally the smaller ones, weakly fluttering over the ripples at the 
water's edge or perching on the vegetation within a foot or two of the 
surface. Not infrequently numbers of them rest among the taller 
grasses of the shady flood plains some distance from the water. Though 
sometimes taken about ponds they are usually much less plentiful 
there. They are especially fond of small streams overshadowed by 
willows and wild cucumber vines. 
C. aequabilis Say. A few specimens were taken in Wabasha and 
Hennepin Counties by Wilson. It is common over the greater part of 
Wisconsin, belonging to the Transition and Upper Austral Zones, and 
the writer possesses several records of it in northern and northeastern 
Iowa. Its habits are very similar to those of C. maculata. 
Genus Hetaerina Hagen. 
H. americana Fabricius. Though not in the Minnesota collections 
and lists at the author’s disposal, this species is sure to be found native 
to the State. It is very generally distributed over the Transition and 
Austral Zones and has been taken by the writer in many counties of 
Iowa, including Dickinson on the Minnesota border. Muttkowski 
records its general distribution in Wisconsin. 
This beautiful species is often found in company with H. tricolor 
and C. maculata along rippling brooks and even larger streams, prob- 
ably never about ponds or lakes. Like the other members of this sub- 
family it is a gregarious species, at times occurring by hundreds over 
small rapids and resting upon protruding rocks or drooping branches 
of willow. On the wing during July, August and September. 
H. tricolor, the nearest relative of H. americana may be found in 
the southern part of the State but not extensively. It has been taken 
as far north as Cherokee County, Iowa, by the writer and apparently 
belongs to the Austral Zone. 
