220 NEW YORK STATE MUSEUM 
b Vein M3 arising (i. e. separating from vein 
Mi+2) nearer the arculus than the nodus...... Lestinae 
bb Vein M3 arising nearer’the nodus than the 
PAP hae ean te, Fs Ut ns Vases oles eve he eee Agrioninae 
Nymphs 
@ Basal segment of the antenna very large, as long 
as the other six together; median lobe of the 
labium with a very deep cleft; gills thick, the 
fateral ones -triquetral:s. oo. je. Fane oes Calopterygidae 
ad Basal segment of antenna not longer than suc- 
ceeding single segments; labium with a very 
shallow closed median cleft or no cleft at all; 
PUSS ELIT, (LATCLEOTIIY soi ce x kyagsie isc wretele Sule. Je comieee Agrionidae 
b Median lobe of labium with a short, closed, 
median cleft; lateral lobe trifid at end; 
movable hook bearing raptorial setae; gills 
showing transverse segmentation............. Lestinge, 
bb Median lobe of labium entire; lateral lobe 
bifid at end; hook naked; gills various....... Agrioninae 
Family CALOFTERYGIDAE 
This family includes in our fauna but two genera, Calopteryx 
and Hetaerina, both of which frequent strong flowing, perma- 
nent streams. The long legged, protectively colored, rather stiff 
and awkward nymphs cling to submerged vegetation, generally 
where it is washed by the current of the stream. 
KEY TO GENERA 
Imagos 
a@ Basal space (space before the arculus) in all wings free 
EPSOM CTOBS Velma. i0. oc. tks bs cele cha one oe ee Calopteryx 
aa Basal space of all wings traversed by cross veins..... Hetaerina 
Nymphs 
a@ Median cleft of the labium extending far below the 
level of the base of the lateral lobes; abdomen with- 
out lateral spines; dorsum of prothorax rounded at 
RAR RAOOD oo a! noid Ein Lee nk Me Eee eee. eee Calopteryx 
aa Cleft of the medium lobe of the labium extending only 
to the level of the base of the lateral lobes; lateral 
margins of abdominal segments 7-9 generally ending 
in small, flattened lateral spines; dorsum of the pro- 
thorax with two angulate teeth each side........... Hetaerina 
