LIBRARY

238
COLLEGE ENTOMOLOGY
and inhabit rocky streams. The adults of Argiolestes, the dominant genus in
Australia, and of Podopteryx rest with their wmgs outspread as do dragonflies.
Species of Podopteryx may have a wing spread of 4 in.
Superfamily AGRIOIDEA I THlyard 1926
KEY TO FAMILIES
1. Wings indistinctly petiolate at base, without a distinct angle on hind
margin at junction of petiole and the rest of the wing; antenodal cross
veins numerous between the costa, sub costa, and radius . 2
Wings distinctly petiolate at base, with a distinct angle on the hind
margin at the junction of the petiole and the rest of the wing; ante·
nodal cross veins few or absent between the costa, subcosta, and
radius . . AMPHIPTERYGIDlE
2. Sectors of arculus arising near or below the middle of arculus; discoidal
cell with opposite sides equal . 3
Sectors of the arculus arising at upper distal corner of arculus, really
from the radius; discoidal cell with the basal side longest POLYTHORIDlE
3. Sectors of the arculu5 arising near middle of arculus; pterostigma dis·
tinct, long . 4
Sectors of the arculus arising from lower part of arculus; pterostigma
often indistinct or obsolete in male; entire wing densely retiCUlate
AGRIIDlE
4. Antenodal cross veins between the costa and radius mostly continuous;
arculus much closer to the wing base than to the nodus EPALLAGIDlE
Antenodal cross veins between the costa and the radius not continuous
beyond the arculus; arculus often about midway between wing base
and nodus . . LIBELLAGINIDlE
Family AGRIIDlE Tillyard 1926 (CALOPTERYGIDJE) (Ag·ri'i·dre, from the
Greek a:ypws, wild, fierce).
A large family of dominant and highly specialized damselflies, widely dis.
tributed and especially well represented in the tropics. The most important
genera are the following: Agrion Fab. (Calopteryx) (Holarctic), Het:erina Hagen
(American), Pentaphlebia Forster and Saplzo Selys (Ethiopian). VestaUs Selys
(Indo.Malaysian), and Neurobosis Selys (Indo-Australasian).
The common ruby spot, Het:erina americana Fabricius, copper·bronze and
metallic green with ruby.red spots covering the bases of boih pairs of wings
of the males which are amber yellow in the females, 44 mm. in length and
having an expanse of 58 mm., is a widely distributed North American species,
abundant along rivers and creeks where the long·legged nymphs live in the
riffles.
I Also known as AGRIONOIDEA.