1a |
a. Basal
subcostal crossvein present |
Progomphus
obscurus (Rambur) |
b. One crossvein
present in forewing subtriangle |
1b |
a. Basal subcostal
crossvein absent |
2 |
b. No crossvein
in forewing subtriangle |
|
2a(1b) |
a. Triangles with
a crossvein |
Hagenius
brevistylus Selys |
b. Each triangle
with a supplementary longitudinal vein (trigonal planate) arising from
its distal side |
c. Hind femora reaching
a little beyond the base of Ab3 |
d. Very large size,
usually > 70 mm in length |
2b |
a. Triangles without
a crossvein |
3 |
b.Without a trigonal
planate arising from its distal side |
c. Hind femora not
reaching beyond middle of Ab2 |
d. Generally < 70
mm in length |
|
3a(2b) |
a. Hind wing with
a semicircular anal loop typically of 3 cells |
Ophiogomphus |
b. Male epiproct
with the 2 branches separated either by a mere slit with the apexes
continguous, or by a U-shaped or V-shaped notch |
c. Female vulvar
lamina nearly as long as Ab9 sternum |
3b |
a. Hind wing with
anal loop absent, or of 1-2 weakly bordered cells |
4 |
b. Male epiproct
with more or less widely separated branches (except Erpetogomphus) |
c. Female vulvar
lamina usually < 0.5x as long as Ab9 sternum |
|
4a(3b) |
Hind femur long,
reaching the base of Ab3, and bearing 4-7 long ventral spines in addition
to the usual short ones |
Dromogomphus |
4b |
Hind femur not extending
beyond the middle of Ab2, and usually bearing only the usual numerous,
short, ventral spines |
5 |
|
5a(4b) |
a. Pterostigma of
fore wing short and thick, at its widest about 2.0x long as wide |
Erpetogomphus designatus Hagen |
b. Hind wing with
5 paranal cells |
c. Branches of male
epiproct long, parallel in its full length, and strongly hooked upward |
5b |
a. Pterostigma of
fore wing usually more elongate, about 3x long as wide |
6 |
b. Hind wing with4-5
paranal cells |
c. Branches of male
epiproct shorter and divergent |
|
6a(5b) |
a. Pterostigma < 4.0x
long as wide, > 2.0x wide as space behind its middle |
Stylogomphus
albistylus (Hagen in Selys) |
b. Male epiproct
with lateral edges subparallel, its 2 branches shorter than the median
length of the appendage |
c. Small, total
length < 40 mm |
also: Outer side
of fore wing slightly angulated near middle; anteclypeus pale; Male
cerci yellow or white, laterally angulate with apexes very slender
and curved upward |
6b |
a. Pterostigma rarely < 4.0x
long as wide, and rarely < 2.0x wide as the space behind its middle |
7 |
b. Male epiproct
with lateral edges widely divergent, its 2 branches longer than the
median length of the appendage |
c. Larger, usually > 40
mm |
|
7a(6b) |
a. Pale species,
with a faint or absent stripe each side of pale middorsal carina of
thorax, and thoracic side stripes much reduced |
Arigomphus |
b. Male with end
hook of posterior hamules long and falciform |
c. Abdomen usually
constricted at Ab9 |
d. Apexes of cerci
usually convergent and very slender |
7b |
a. Usually a darker
species, with conspicuous dark stripes on thorax |
8 |
b. Male posterior
hamule often with a sharp shoulder, but the end hook is not so long
or falciform |
c. Abdomen usually
not constricted at Ab9 |
d. Cercal apexes
variable, but not convergent or very slender |
|
8a(7b) |
a. Top of frons
4.0x wide as long |
Stylurus |
b. Male cerci simple,
horizontal, without angular processes and only rarely with the lateral
margins angular |
c. Branches of male
epiproct diverging at about the same angle as the cerci, usually obscured
in dorsal view |
d. Anterior hamules
vestigial, slender, unarmed and difficult to see, wheras the posterior
hamules are usually upright or leaning forward |
e. Anterior lamina
of male flat, not projecting above the rim of the genital pocket |
f. Female vulvar
lamina very short, sometimes vestigial |
8b |
a. Top of frons
about 3.0x wide as long |
Gomphus complex, 9 |
b. Male cerci usually
with sharply angular processes |
c. Branches of male
epiproct often diverge more strongly than cerci, thier apexes conspicuous
in dorsal view |
d. Anterior hamules
of male not vestigial, always bearing at least 1 hook or spine, and posterior
hamules upright or leaning backward |
e. Male anterior
lamina usually projecting above the rim of the genital pocket |
f. Female vulvar
lamina variable, often 0.5x long as Ab9 |
|
9a(8b) |
a. Width of head about 0.8x the length of the metafemora, or less |
Gomphurus Needham |
b. Forewings each with the anterior side of the triangle shorter than the proximal side |
c. Large species, hindwing usually 32mm or longer, with Ab8-10 strongly expanded |
9b |
a. Width of head distinctly >0.8x the length of the metafemora, usually >0.9x that length |
10 |
b. Forewings each with the anterior side of the tirangle longer than the proximal side |
c. Smaller species, or if hindwings longer than 32mm, then Ab8-10 not strongly expanded |
|
10a(9b) |
a. Middorsal length of Ab8 < than 0.75x that of Ab9 |
Hylogomphus Needham, Westfall and May |
b. Males with the outer apical edge of the anterior hamules denticulate |
c. Females with subgenital plate more than 1/2 the length of Ab9 sternum, and divided for much less than 1/2 its length |
10b |
a. Middorsal length of Ab8 < than 0.75x that of Ab9 |
Phanogomphus Carle |
b. Males with the outer apical edge of the anterior hamules spinose or hook-like |
c. Females with subgenital plate not more than 1/3 the length of Ab9 sternum, and, if nearly 1/3 as long, then divided for more than 1/2 its length |
|