Diagrammatic Key - Dragonflies

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Family Aeshnidae in B.C.
The Blue Darners

Diagrammatic Key

Dragonflies with eyes meeting broadly on top of head (1); body longer than 50 mm; each abdominal segment with multiple blue, green or yellow spots, or none; wings without dark markings (except for the stigma, the small coloured cell near the wing tip) _____Aeshnidae

Thorax (body section bearing wings and legs) entirely green *Green Darner (Anax junius)*	Thorax dark with pale, coloured stripes on sides *Blue Darners (Aeshna)*

Males - three terminal appendages on abdomen(2)	Females - two terminal appendages on abdomen (3) SEE FEMALE

anal triangle at base of hind wing with two cells (4) SEE ANAL TRIANGLE	anal triangle with three cells (5)

superior appendages at tip of abdomen forked in side view (6) eyes, face and thoracic stripes bright sky blue stripes straight (7) Blue-eyes Darner (Aeshna multicolour)	superior appendages simple or paddle-shaped, not forked (8, 9) eyes, face and thoracic stripes coloured otherwise

superior appendages paddle-shaped, with small spine at tip (8) lateral thoracic stripes usually with some yellow colour medium-sized, usually 65 mm or longer	superior appendages simple (9) lateral thoracic stripes straight, without yellow colour (10) face pale blue or green with black line (11) small, less than 65 mm long *California Darner (Aeshna californica)*

rear of head partly yellow no blue spots on top of last abdominal segment underside of abdominal segments with blue spots lateral thoracic stripes straight (12) *Shadow Darner (Aeshna umbrosa)*	rear of head all black blue spots on top of last abdominal segment (13) no blue spots on underside of abdominal segments

face light green/yellow with fine light brown line front lateral stripe indented in middle (14) *Lance-tipped Darner (Aeshna constricta)*	face light green/yellow with black line front lateral stripe straight edged, often slightly wavy in front (15) *Paddle-tailed Darner (Aeshna palmata)*

ANAL TRIANGLE
SECTION

anal triangle at base of hind wing with two cells

species small, less than 60 mm long
front thoracic stripe thin, strongly bent in middle (16)

species longer than 60 mm
front lateral stripe straight, divided or indented, but not bent (17, 18)

T-spot on top of face lobed at base (19)
face often with some yellow colour
Zigzag darner (Aeshna sitchensis)

T-spot flat at base (20)
face blue/green
Azure Darner (Aeshna septentrionalis)

last segment of abdomen with pale spots on top

last segment of abdomen black, without pale spots
lateral thoracic stripes broad and straight in front (21)
superior appendage with tubercle under base (22)Black-tipped Darner (Aeshna tuberculifera)

face light green with thin, light brown line
front lateral thoracic stripe indented in middle (23)Canada Darner (Aeshna canadenxix)

face yellow or yellow/green with black line

lateral thoracic stripes narrow and straight (24) or reduced to pairs of spots (25)
stripes on front of thorax reduced to fine streaks at mid-height
Variable Darner (Aeshna interrupta)

lateral thoracic stripes well developed, more than 1 mm broad (26, 27 & 28)
stripes on front of thorax broad extending to upper edge or represented there by isolated spots

lateral thoracic stripes straight (26)
Sedge Darner
(Aeshna juncea)

front lateral thoracic stripes indented in middle (27, 28)

front lateral stripe indented abruptly in middle (27)
lateral stripes without yellow colour, usually blue/green or purple
large; usually longer that 72 mm
Lake Darner (Aeshna eremita)

front lateral stripe gently narrowed in middle (28)
lateral stripes with some yellow colour
medium-sized; usually less than 70 mm long Subarctic Darner (Aeshna subarctica)

FEMALES SECTION
CONTINUED

two terminal appendages on abdomen

front lateral thoracic stripe thin, strongly bent in middle (29)
small for family (60 mm or less)

front lateral stripe otherwise; not as in 29
usually averaged sized for family (60 mm or longer - except often for California Darner)

T-spot on top of face lobed at base (30) Zigzag Darner (Aeshna sitchensis)

T-spot flat at base (31) Azure Darner (Aeshna septentrionalis)

no tubercle under first abdominal segment
SEE TUBERCLE

small but distinct tubercle (bump) under first abdominal segment (look carefully from the side!) (32)

small species (usually 60 mm long or less)
face with black line (34)
lateral thoracic stripes as in 33 California Darner (Aeshna californica)

average-size (65 mm or longer)
face with faint brown line (34)
lateral thoracic stripes as in 35 Blue-eyed Darner (Aeshna multicolor)

NO TUBERCLE SECTION
CONTINUED

no tubercle under first abdominal segment

styli of ovipositor as long as length of last abdominal segment (36a)
terminal appendages 2 mm wide or more (36b)
rare species

styli much shorter than length of last abdominal segment (37a)
terminal appendages 1.5 mm wide (37B)
most common species

front lateral thoracic stripe narrowed in middle and usually hooked at upper end (38)
lateral thoracic stripes with some yellow colour Lance-tipped Darner (Aeshna constricta)

lateral thoracic stripes more similar in shape, straight-edged (39)
lateral thoracic stripes blue and green, no yellow colour
Black-tipped Darner (Aeshna tuberculifera)

underside of most abdominal segments with a light basal spot on each side

underside of abdomen entirely dark SEE UNDERSIDE

face with faint brown line

face with black line

lateral thoracic stripes straight (40) Shadow Darner (Aeshna umbrosa)

lateral thoracic stripes as in 41 Canada Darner (Aeshna canadensis)

both lateral thoracic stripes broad and straight (42) Sedge Darner (Aeshna juncea)

lateral thoracic stripes indented in middle (43 Subarctic Darner (Aeshna subarctica)

UNDERSIDE SECTION
CONTINUED

underside of abdomen entirely dark

front lateral thoracic stripe distinctly indented in middle (44)
face with black line Lake Darner (Aeshna eremita)

both lateral thoracic stripes straight-sided, often with wavy edge in front (45, 47); often very narrow (47) or divided into spots (48)

lateral thoracic stripes as in 45
ovipositor valves 3 to 3.5 mm long (46) Paddle-tailed Darner (Aeshna palmata)

lateral thoracic stripes as in 47 or 48
ovipositor valves 2 to 2.5 mm long (49) Variable Darner (Aeshna interrupta)