Dragonflies of Sri Lanka

GEHAN'S PHOTO GUIDE
Dragonflies of Sri Lanka
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A Conservation Project
Jetwing
A Photographic Guide to the
Dragonflies of Sri Lanka
Matjaž Bedjanič
Karen Conniff
Gehan de Silva Wijeyeratne
Gehan’s Photo Guides
Gehan’s Photo Guide series is published by Jetwing Eco
Holidays, a standard setting wildlife travel company. Jetwing
Eco Holidays would like to thank its Jetwing associates,
industry counterparts, service suppliers and clients for their
support to make it a force for conservation.
Wildlife populariser Gehan de Silva Wijeyeratne has enlisted
the support of many individuals on a crusade to create a
million, knowledgeable wildlife enthusiasts, by the year 2025.
One of the primary objectives of the Photo Guide series is
to enable a broad spectrum of people from school children
to safari jeep drivers to other interested adults to be able
to know a plant or animal by its name. This is an important
and key step for creating awareness and hence support for
conservation.
Everyone can contribute to conservation by something as
simple as setting aside a few square feet in a back garden
to run wild. This will create a habitat for native plants and
animals. The Photo Guide Series will help people to put a
name to what they see and appreciate the diversity of life.
First Edition: October 2007
First Print: October 2007
Published by: Jetwing Eco Holidays.
Citation: Bedjanič, M., Conniff, K., de Silva Wijeyeratne, G.
(2007). Gehan’s Photo Guide. A Photographic Guide to the
Dragonflies of Sri Lanka. Jetwing Eco Holidays: Colombo. ISBN
978-955-1079-15-4
© The intellectual rights of the authors and photographers are
asserted.
Contents
Foreword...................................................... 4
Introduction to Dragonflies................................. 6
Life Cycle & Ecology......................................... 7
Dragonfly Conservation....................................10
Morphology...................................................11
Sri Lanka Odonate Checklist..............................15
Simple key to suborders and families
of adult dragonflies of Sri Lanka.......................19
Species Accounts............................................23
Dragonfly Glossary........................................ 232
Dragonfly literature for Sri Lanka...................... 234
Natural History Organisations........................... 238
Useful Natural History books............................ 240
The Authors & Photographers........................... 243
Acknowledgements....................................... 245
Notes........................................................ 247
Foreword
Dragonflies are very interesting and diverse insects.
They instantly attract attention with their amazing
flight skills and beautiful colours. Dragonflies mostly
occur in the vicinity of different fresh water habitats
like rivers, streams, marshes, lakes and even small
pools and rice fields. Most species are seen as solitary
individuals or in pairs during mating, although a few
species occasionally occur in swarms. Observing them
might be difficult at first, but after some practice it
becomes easier. Understanding the behavior of different
dragonfly and damselfly species helps with finding and
observing them; this comes with timing and practice.
Be patient.
Dragonflies are aggressive predators in the larval form
as well as the winged adult. Their habit of sallying out
from a favourite perch to catch prey provides good
opportunities for patient observation. Providing a few
upright sticks in the garden or a small nicely vegetated
pool is an easy way of attracting dragonflies. A slow
approach with a pair of close focusing binoculars will
offer excellent views. Photographing dragonflies in
the early morning is best when they are bit sluggish.
However, the sunniest and hottest part of the day is
even better, since dragonflies are true sun fans. Note
how individuals perch along the axis of a stem, offering
the best angle for photography. The Anisopterans
usually hold their wings horizontal, but as the sun
warms them they will hold their wings up or turned
forward, to reduce the effects of heating. And of
course, despite their size, bright colours and strong
flight, these beautiful insects are completely harmless
to humans – they don’t bite, sting and are not harmful
in any way.
It is hoped that the photographic plates in this guide
will help newcomers to natural history place a name
on the dragonflies they see around them. This book is
intended to be a layman’s guide to field identification.
However, it does not cover all species of dragonflies
recorded in Sri Lanka. Several species have not been
seen in more than sixty years, some may even be
extinct and lost forever, and several are in the process
of being reclassified while others have not yet been
photographed. Nevertheless, it is an important step
forward. It is the first photographic guide book to the
dragonflies of Sri Lanka in any language. Since many
of the species in this guide are also found in India it
is hoped that this book will have a wider application
beyond Sri Lanka.
Present knowledge concerning biology, ecology and
distribution of many less common species is still
fragmentary. The information presented in this book is
based on field work experience of the authors as well
as on all published and unpublished information on
dragonfly species occurring in Sri Lanka. Nevertheless,
the status of some species is probably open to
considerable revision.
Introduction to Dragonflies
Dragonflies and Damselflies
What are loosely referred to as Dragonflies are in fact
three suborders with two suborders present in Sri
Lanka. Dragonflies are in the suborder (Anisoptera)
and Damselflies are in the suborder (Zygoptera),
both belonging to Odonata. The Odonata are one of
the smaller orders of insects numbering around 6,000
species world-wide. This is an ancient order with fossil
records dating back to the Permian era 230 – 280 million
years ago.
Sri Lanka’s Dragonfly fauna
Sri Lanka has 117 species of dragonflies and damselflies
of which an astonishing 53 are endemic. The high
occurrence of endemics makes them an important
group in the study of Sri Lankan biodiversity. This guide
provides photos of 91 species of which 34 are endemic.
This collection of photos is a major step forward in
understanding dragonflies, their habitat and brings
awareness to the fragile conditions necessary for their
survival.
Little is known of this faunal group in Sri Lanka including
basic data on life cycles and larvae. Some very interesting
species found in recent years still await description and
it is quite likely that many additional ones are yet to be
recorded and described. The excitement of describing
a new species is only dampened by the realization that
the island may have lost species before science could
catch up with them.
Life Cycle & Ecology
Incomplete metamorphosis – the life cycle consisting of
egg and several larval instars followed directly by the
adult phase – is characteristic of dragonflies. Beautifully
coloured adult winged insects, which can be met along
rivers, streams, paddy fields, marshes, pools and lakes
almost year round, represent only the shorter phase of
their life cycle. They spend most of their lives hidden
from human eyes as larvae in the water.
Larvae develop from eggs, which, depending on species,
were laid by females in plant tissue or dropped freely
into the water. The first larval instar is very small, but
after several moults the larvae become proportionally
larger. Larvae appear as rough bodied clumsy looking
creatures with spidery legs and have very little in
common with the beautiful winged adults. Both adults
and larvae are voracious eaters and very successful
predators. All dragonfly larvae have a modified lower
lip, which is innocently folded beneath the head at
rest but can grasp prey with lightning speed. They feed
on smaller water insects, including mosquito larvae
and occasionally even small fishes. Swollen wing pads
of fully grown larva clearly declare that it is ready
to emerge. It climbs out of the water and emerges
from an unbearably tight larval casing; remarkably
the teneral adult quickly expands its soft wings and
flies away before even developing brighter colours.
Initially, newly emerged, adults indulge in feeding and
their attractive colouration develops only after several
days. During the pre-reproductive period and while
feeding, the adults are often encountered far from
their breeding places.
FIGURE 1: The life cycle of a dragonfly: (1) mating, (2) egg-laying, (3-6) larval
development, (7) last moulting – emergence, (8) adult insect. (Drawing: M.
Bedjanič)
Male dragonflies are usually found on or near water
environments; besides feeding, their main occupation
seems to be an active search for a mate. Females live
away from water and are mostly seen on the water
when they mate or lay eggs, otherwise, they dwell and
feed at forest edges and clearings to avoid contact with
the males.
Mating in dragonflies is something special and is
definitely one of the most interesting acts in nature. It
is interesting that male’s and female’s primary sexual
organs, which are situated at the end of abdomen,
are not in direct contact during mating. Underneath
the second and third abdominal segment, the male
has so called secondary genital organs where sperm
is transferred from the abdomen tip. The female, still
securely held by the male’s anal appendages, bends her
abdomen and genitalia to the secondary genitalia of
the male and the partners are joined. This beautiful
heart-shaped figure is called a “wheel” or “copula”.
For additional relevant information regarding dragonfly
biology and ecology the reader is referred to more
comprehensive dragonfly publications such as CORBET
(1999), de Fonseka (2000) and ORR (2003).
Dragonfly Conservation
Dragonflies are often addressed as “guardians of the
watershed”. In nature they appear at two levels – they
are the subjects of conservation concerns as endangered
species and as indicators of wetland habitat quality. In
different stages of their lives, dragonflies occur both in
terrestrial and freshwater habitats and are sensitive to
disturbances in both. While habitat selection of adult
insects strongly depends on vegetation structure, their
larvae develop in water and are critical in regard to
water quality and aquatic habitat structure. Therefore,
along with birds and amphibians, dragonflies can serve as
one of the key bio-indicator groups, whose high species
diversity clearly mirrors favourable conservation of the
wider wetland ecosystems.
Although dragonflies are generally considered to have
little economic significance, both larvae and adults
are predators near the top of food chains in their
ecosystems. Some species feed chiefly on mosquitoes
and their larvae. Thus, in some regions, their potential
for pest control in paddy fields is substantial.
In Sri Lanka, case studies of dragonflies are urgently
required for additional baseline data on biology and
ecology of selected species in order to facilitate even
wider applied research, conservation measures and
long-term monitoring schemes.
10
Morphology
Knowledge of dragonfly morphology, including many minute
details, is absolutely essential to determine individual
species. In this book an attempt has been made to reduce
the technical side to an acceptable level. But first it will
help to answer some basic questions about what type of
dragonfly you might see; “Does it belong to Zygoptera or
Anisoptera?”, “Is it a male or a female?”, “Is it an adult,
a juvenile or teneral?” With this sorted out, the next
step is a family ranking lottery. Try to remember main
characteristics found in the “Key to the suborders and
families” chapter. After some experience, a quick look will
be all that is needed to successfully determine the family.
The choice of photos in the book will become narrower
and the final answer much easier.
Damselfly or dragonfly?
As pointed out earlier, the dragonflies of Sri Lanka can be
divided into two suborders – damselflies (Lat. Zygoptera)
and dragonflies (Lat. Anisoptera). The broadly applied
term “dragonflies” applies to both suborders.
Damselflies (Zygoptera) are generally small and delicate
insects with hammer-shaped head on which the compound
eyes are well separated, match-like slender abdomen and
essentially equally shaped narrow wings (Fig. 2), which at
rest are folded over abdomen or are slightly spread.
11
FIGURE 2: Wing morphology of a damselfly (Zygoptera, family Coenagrionidae).
Dragonflies (Anisoptera) are generally larger and more
robustly built insects, in which large compound eyes
cover almost the entire head. Their hindwings are always
expanded at the base (Fig. 3), the venation of fore and
hindwings differs substantially and at rest, the wings are
broadly opened.
FIGURE 3. Wing morphology of a dragonfly (Anisoptera, family Corduliidae).
Apart from abdomen and wing length measurements given
in the book, which can vary considerably and are only
approximate, colour and markings can also vary depending
on sex and age of the individual.
12
This is one of the reasons that scientific work and species
determination is often based on stable minute structural
characters, such as the shape of a female’s prothorax or
the shape of anal appendages in males. For the purpose of
this book and field observation guidance for the general
naturalist this would be too complicated and a sound
compromise is needed.
Male or a female?
In dragonflies, mature males and females often look very
different, the males regularly being more conspicuous and
brightly coloured. However, freshly emerged and young
males often resemble paler females in colouration. Wing
venation and often patterns on the thorax are not sex
dependant.
Since males are more common near water, the majority
of individuals observed are likely to be males. Generally
quite similar individuals will vary slightly in colouration;
this may be age dependant and does not necessarily mean
that there are two species in front of you.
But returning to the above question: males can be
recognised by the secondary genitalia, which are distinctly
protruding under the abdomen like a pinhead, best visible
from the side (Fig.4). They also have differently shaped
anal appendages at the abdomen tip which are used to
hold a female’s head or neck during mating.
13
Females’ abdomens in Zygoptera have thicker terminal
ends due to distinct ovipositors; an organ below the
abdomen tip, used to lay eggs in plant tissue. In Anisopteran
families, because females lay eggs directly into the water
they have reduced simple straight shaped ovipositors.
Here, presence of two simple straight appendages at the
abdomen tip might be useful in confirming their sex.
FIGURE 4. General morphology of an adult dragonfly (Anisoptera, family Gomphidae).
14
Sri Lanka Odonate Checklist
Suborder Zygoptera - Damselflies
Family Calopterygidae - Jewelwings
Oriental Green-wing (Neurobasis chinensis chinensis)
Black-tipped Flashwing (Vestalis apicalis nigrescens) E
Family Chlorocyphidae - Jewels
Adam’s Gem (Libellago adami) E
Ultima Gem (Libellago finalis) E
Green’s Gem (Libellago greeni) E
Indian Yellow-lined Gem (Libellago lineata indica)
Family Euphaeidae - Gossamerwings
Shining Gossamerwing (Euphaea splendens) E
Family Lestidae - Spreadwings
Scalloped Spreadwing (Lestes praemorsus decipiens)
White-tipped Spreadwing (Lestes elatus)
Malabar Spreadwing (Lestes malabaricus)
Emerald Sri Lanka Spreadwing (Sinhalestes orientalis) E
Metallic-backed Reedling (Indolestes divisus) E
Mountain Reedling (Indolestes gracilis gracilis) E
Family Coenagrionidae - Bluets
White-backed Wisp (Agriocnemis femina)
Wandering Wisp (Agriocnemis pygmaea pygmaea)
Sri Lanka Midget (Mortonagrion ceylonicum) E
Marsh Dancer (Onychargia atrocyana)
Malay Lilysquatter (Paracercion malayanum)
Little Blue (Enallagma parvum)
Asian Slim (Aciagrion occidentale)
Dawn Bluetail (Ischnura aurora aurora)
Common Bluetail (Ischnura senegalensis)
Painted Waxtail (Ceriagrion cerinorubellum)
Yellow Waxtail (Ceriagrion coromandelianum)
Malabar Sprite (Pseudagrion malabaricum)
15
Pg. 28
Pg. 30
Pg. 34
Pg. 36
Pg. 38
Pg. 42
Pg. 46
Pg. 48
Pg. 50
Pg.
Pg.
Pg.
Pg.
Pg.
54
56
58
60
62
Pg.
Pg.
Pg.
Pg.
Pg.
64
66
68
70
72
Blue Sprite (Pseudagrion microcephalum)
Pg. 74
Azure Sprite (Pseudagrion decorum)
Pg. 76
Sri Lanka Orange-faced Sprite (Pseudagrion rubriceps ceylonicum) E Pg. 78
Family Platycnemididae - Featherlegs
Yellow Featherleg (Copera marginipes)
Pg. 82
Family Platystictidae - Forestdamsels
Adam’s Shadowdamsel (Drepanosticta adami) E
Austin’s Shadowdamsel (Drepanosticta austeni) E
Brinck’s Shadowdamsel (Drepanosticta brincki) E
Pg. 86
Nobel Shadowdamsel (Drepanosticta digna) E
Fraser’s Shadowdamsel (Drepanosticta fraseri) E
Merry Shadowdamsel (Drepanosticta hilaris) E
Drooping Shadowdamsel (Drepanosticta lankanensis) E
Pg. 88
Dark Knob-tipped Shadowdamsel (Drepanosticta montana) E
Pg. 90
Nietner’s Shadowdamsel (Drepanosticta nietneri) E
Pg. 92
Sinhalese Shadowdamsel (Drepanosticta sinhalensis) E
Pg. 94
Starmühlner’s Shadowdamsel (Drepanosticta starmuehlneri) E
Bordered Knob-tipped Shadowdamsel (Drepanosticta submontana) E
Blue-shouldered Cornuted Shadowdamsel (Drepanosticta subtropica) E
Dark-shouldered Cornuted Shadowdamsel (Drepanosticta tropica) E Pg. 96
Wall’s Shadowdamsel (Drepanosticta walli) E
Dark Forestdamsel (Platysticta apicalis) E
Pg. 98
Blurry Forestdamsel (Platysticta maculata) E
Pg. 100
Family Protoneuridae - Threadtails
Ramajana Bambootail (Disparoneura ramajana) E
Two-spotted Threadtail (Elattoneura bigemmata) E
Jungle Threadtail (Elattoneura caesia) E
Dark-glittering Threadtail (Elattoneura centralis) E
Smoky-winged Threadtail (Elattoneura leucostigma) E
Red-striped Threadtail (Elattoneura tenax) E
Stripe-headed Threadtail (Prodasineura sita) E
16
Pg. 104
Pg. 106
Pg. 108
Pg. 110
Pg. 112
Suborder Anisoptera - Dragonflies
Family Gomphidae - Clubtails
Solitaire Clubtail (Anisogomphus solitaris) E
Sinuate Clubtail (Burmagomphus pyramidalis sinuatus) E
Transvestite Clubtail (Cyclogomphus gynostylus) E
Sri Lanka Sabretail (Megalogomphus ceylonicus) E
Brook Hooktail (Paragomphus henryi) E
Sri Lanka Grappletail (Heliogomphus ceylonicus) E
Lyrate Grappletail (Heliogomphus lyratus) E
Nietner’s Grappletail (Heliogomphus nietneri) E
Wall’s Grappletail (Heliogomphus walli) E
Keiser’s Forktail (Macrogomphus annulatus keiseri) E
Sri Lanka Forktail (Macrogomphus lankanensis) E
Wijaya’s Scissortail (Microgomphus wijaya) E
Rivulet Tiger (Gomphidia pearsoni) E
Rapacious Flangetail (Ictinogomphus rapax)
Family Aeshnidae - Hawkers
Pale-spotted Emperor (Anax guttatus)
Fiery Emperor (Anax immaculifrons) Elephant Emperor (Anax indicus)
Vagrant Emperor (Anax ephippiger)
Indian Duskhawker (Gynacantha dravida)
Dark Hawker (Anaciaeschna donaldi)
Family Corduliidae - Emeralds
Blue-eyed Pondcruiser (Epophthalmia vittata cyanocephala) E
Flint’s Cruiser (Macromia flinti) E
Sri Lanka Cruiser (Macromia zeylanica) E
Pg.
Pg.
Pg.
Pg.
Pg. 124
Pg.
Pg.
Pg.
Pg.
126
128
130
132
Pg.
Pg.
Pg.
Pg.
Pg.
136
138
140
142
144
Pg. 148
Pg. 150
Family Libellulidae - Chasers
Fruhstorfer’s Junglewatcher (Hylaeothemis fruhstorferi fruhstorferi) EPg.
Yerbury’s Elf (Tetrathemis yerburyii) E
Pg.
Sombre Lieutenant (Brachydiplax sobrina)
Pg.
Pale-faced Forestskimmer (Cratilla lineata calverti)
Pg.
Pruinosed Bloodtail (Lathrecista asiatica asiatica)
Pg.
Spine-tufted Skimmer (Orthetrum chrysis)
Pg.
Asian Skimmer (Orthetrum glaucum)
Pg.
Marsh Skimmer (Orthetrum luzonicum)
Pg.
17
116
118
120
122
154
156
158
160
162
164
166
168
Pink Skimmer (Orthetrum pruinosum neglectum)
Green Skimmer (Orthetrum sabina sabina)
Triangle Skimmer (Orthetrum triangulare triangulare)
Blue Pursuer (Potamarcha congener)
Asian Pintail (Acisoma panorpoides panorpoides)
Asian Groundling (Brachythemis contaminata)
Indian Rockdweller (Bradinopyga geminata)
Oriental Scarlet (Crocothemis servilia servilia)
Black-tipped Percher (Diplacodes nebulosa)
Blue Percher (Diplacodes trivialis)
Light-tipped Demon (Indothemis carnatica)
Restless Demon (Indothemis limbata sita)
Paddyfield Parasol (Neurothemis intermedia intermedia)
Pied Parasol (Neurothemis tullia tullia)
Spine-legged Redbolt (Rhodothemis rufa)
Red-veined Darter (Sympetrum fonscolombii)
Crimson Dropwing (Trithemis aurora)
Indigo Dropwing (Trithemis festiva)
Dancing Dropwing (Trithemis pallidinervis)
Aggressive Riverhawk (Onychothemis tonkinensis ceylanica)
Asian Widow (Palpopleura sexmaculata sexmaculata)
Sapphire Flutterer (Rhyothemis triangularis)
Variegated Flutterer (Rhyothemis variegata variegata)
Amber-winged Glider (Hydrobasileus croceus)
Wandering Glider (Pantala flavescens)
Burmeister’s Glider (Tramea basilaris burmeisteri)
Sociable Glider (Tramea limbata)
Foggy-winged Twister (Tholymis tillarga)
Dingy Duskflyer (Zyxomma petiolatum)
Elusive Adjutant (Aethriamanta brevipennis brevipennis)
Coastal Pennant (Macrodiplax cora)
Scarlet Basker (Urothemis signata signata)
Sri Lanka Cascader (Zygonyx iris ceylonicum) E
Shaded lines indicate species that have not been included in this guide.
E beside the species name indicates endemic species.
18
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
170
172
174
176
178
180
182
184
186
188
190
192
194
196
198
200
202
204
206
208
210
212
214
Pg.
Pg.
Pg.
Pg.
Pg.
Pg.
216
218
220
222
224
226
Pg. 228
Pg. 230
Simple key to suborders and families
of adult dragonflies of Sri Lanka
Key to Suborders
Slender insects with eyes well
separated by a space greater than their
own diameter. Forewings and hindwings
are essentially similar in shape and
venation, narrow at base.
Robust insects with eyes usually
touching broadly along the mid line, or
if separated, never by a space greater
than their own diameter. Hindwing
expanded at base. Venation of forewing
and hindwing very different.
Key to Families of Zygoptera
1a Numerous antenodal crossveins
in the costal space of both wings.
Wings often coloured, sometimes
iridescent.
1b Only two antenodal crossveins in
the costal space. Wings hyaline.
Zygoptera
Anisoptera
2
4
2a Very small stout species with Chlorocyphidae
abdomen shorter than hindwings.
(pp. 32)
Front of head produced to form
a projecting rostrum or “nose”;
hindwings 15-30 mm.
2b Larger species, abdomen clearly
3
longer than hindwings.
19
3a Larger species with long-legs. Calopterygidae
Head, thorax and abdomen mostly
(pp. 26)
bright metallic green. Hindwings
32-38mm.
3b Robust species with short legs and
forewings longer than hindwings.
Head, thorax and abdomen never
metallic green. Hindwings 3035mm.
Euphaeidae
(pp. 40)
4a Numerous supplementary veins
inserted between the main veins
from the distal wing margin to the
level of pterostigma. Pterostigma
large, narrow, distinctly longer
than broad.
Lestidae
(pp. 44)
4b Supplementary veins absent from
the wing tip, or if present, only
to the depth of 1-2 cells only.
Pterostigma only slightly longer
than broad or diamond shaped.
5
5a Anal vein absent or very poorly
developed, never extending beyond
distal end of quadrilateral.
5b Anal vein well developed, extending
at least two cells beyond distal end
of quadrilateral.
6
20
7
6a Tip of wings not evenly rounded, Platystictidae
slightly angulated. Brown or black
(pp. 84)
coloured damselflies with azure
blue markings on abdomen.
6b Tip of wings evenly rounded. Protoneuridae
Totally or partly black with orange,
(pp. 102)
yellowish or whitish markings,
never with azure blue markings on
abdomen.
7a Head narrow, striped, length to Platycnemididae
width ratio more than 1:4. Femora
(pp. 80)
and tibiae with many spines. Never
with blue or green markings.
7b Head broad, length to width ratio Coenagrionidae
approximately 1:3. Often with blue
(pp. 52)
or green markings.
Key to Families of Anisoptera
1a Eyes clearly separated. Makes
flights from a perch, without flying
continuously for long periods.
1b Eyes broadly contiguous or at least
touching.
21
Gomphidae
(pp. 114)
2
2a Triangles similarly oriented in both
wings, with sharp angles pointing
to the wing tips. Females with
well-developed ovipositor. Never
metallic, often at least partly blue
or green coloured. Large species,
constant fliers.
Aeshnidae
(pp. 134)
2b Triangles differently oriented,
with sharp angles pointing to the
abdomen tip in the forewing and to
the wingtips in hindwing. Females
lacking ovipositor.
3
3a Posterior eye margin with prominent
bulge. Thorax and abdomen often
dark metallic green with yellowish
markings, never predominantly
yellowish, brown, red or blue.
Constant tireless fliers.
Corduliidae
(pp. 146)
3b Posterior eye margin without
prominent bulge. Thorax and
abdomen only very rarely metallic.
Predominantly yellowish, brown,
red or blue coloured, abdomen
often priunosed in males. Makes
flights from a perch without flying
continuously for long periods.
Libellulidae
(pp. 152)
22
Species Accounts
All species accounts are similarly structured and
explained in the following paragraphs.
Name Common names in English, Sinhala and Tamil
langauges are used for convenience but common names
may not be the same between Sri Lanka and India or
other locations in Asia. To avoid possible confusion the
scientific name is also used. The scientific name can
help overcome the variation in common names.
Male Usually more obvious due to position on or near
water and due to colouration. A brief field description
is given to help confirm the sighting of certain species.
Some specific identification features will be included in
an insert to clarify further.
Female Can be similar to the male or quite different
depending on the species and age of the female.
Because females are encountered less often and are
more difficult to photograph they are not always
included on the following pages. A brief description will
be given for most females unless the female is still not
described or has yet to be found.
Measure line The line shown is only a rough indication
of the approximate natural length of the species in the
photographs.
23