Famity AESCHNIDAE 
KEY* TO THE SUBFAMILIES 
Adults 
1 Stigma with a brace vein at its innerend.................... 2. 
Stigma without brace vein at inner end. .Cordulegasterinae, p. 152 
2 Fore wing, anal vein apparently forked before the triangle...... 
Mer os ces St acas cod ie Lee arene PME teenie nes nee Petalurinae, p. 53 
Fore wing, anal vein extends direct to hind angle of triangle...... 3. 
3 Eyes widely separated on top of head. ....... Gomphinae, p. 58 
Eyes meeting on top of head................ Aeschninae, p. 123 
Nymphs 
abium fat; \Or NEarlvason ee fe ceo Seed oe ae a ee een cee 2. 
Wain SpOOn SHaNed sn ts. oo ee Cordulegasterinae, p. 152 
2 Tarsi 2-2-3 jointed; antennae 4 jointed; burrowing nymphs 
Pirie a EP an ise RS ay. tiniest pie os ier ade ead Oe Gomphinae, p. 59 
Tarsi 3-3-3 jointed; antennae 7 jointed.....................- 3. 
So antennae. Chicks... aibecenes wipers hie gee ok cs oe Petalurinae, p. 54 
AmfPennae SECACCOUSs on <tea:a. Aisa o cutee cals cnseneh: Aeschninae, p. 123 
* It is assumed that the user of this Handbook has some elementary knowl- 
edge of insects; but if not, the parts are named (so far as needed) on the figures 
of the preceding pages; terms not so named will be found in any good English 
dictionary. He should know that insects, like other animals, are grouped suc- 
cessively into Orders, Families, Genera, and Species; that by common consent 
Family names end in idae and subfamily names in inae; and that in order to 
use a “key’’ for determining specimens he has only to choose between the 
alternatives offered and follow the numerals in the margin to the destination 
indicated. 
SUBFAMILY PETALURINAE 
These are large, hairy dragonflies of obscure grayish coloration. 
The eyes are widely separated on the top of the head. The labium 
is divided at the tip by a median cleft. The triangles of fore and hind 
wings are similar in form and nearly equilateral. In the fore wing the 
anal vein appears as if forked before the triangle. The stigma is long 
and narrow, with a well developed brace vein at its inner end. 
The nymphs, so far as known, are rough, angular, thick-set, hairy 
creatures that live in the mud of bogs. 
53 
