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Glossary

A   B    C   D    E   F    G   H    I   J    K   L    M   N    O   P    Q   R    S   T    U   V    W   X    Y   Z

A

abdomen - The last, and the usually largest, of the three portions of an insects body.  It begins after the thorax.  It usually is made up of anywhere from 8-11 segments.

abdominal segments - The ten separate parts making up the abdomen.  Joints between the segments allow the dragonfly to bend easily, this is important when dragonflies mate and lay their eggs.  Usually numbered from S1 through S10 from the thorax to the tip. These segments usually show varied patterns of coloration crucial in the identification of certain species.

andromorph - female form which is similar to the male of the species

Anisoptera - suborder of Odonata, specifically dragonflies

antennae - Located at the top of the dragonfly's head, these bristle like projections help the dragonfly sense its surroundings.  It is thought to aid in the capturing of prey at night and may also serve as airspeed indicators.

anterior - towards the front of the odonate

B,C

biological diversity - the variety of life in all its forms, levels and combinations including ecosystem diversity, species diversity and genetic diversity

biome - A group of ecosystems that are related by having a similar type of vegetation governed by similar climatic conditions. Examples include prairies, deciduous forests, arctic tundra, deserts, and tropical rain forests.

bog - a wetland that has poorly drained acidic peat-soil dominated by sedges and sphagnum moss

brackish - somewhat salty water, as in an estuary

broad-spectrum pesticides - chemical pesticides that kill a wide range of pests.  These pesticides also kill a wide range of non-pest and beneficial species.

carnivore - species that feeds on other organisms

caudal - toward the end or posterior end of an organism

caudal lamellae - terminal gill filaments of the damselfly larvae (Zygoptera) which are usually flat and broad

cerci - appendages on terminal abdominal segment

cercus - one cerci - an appendage on the terminal abdominal segment

channelization - the straightening and deepening of stream or river channels to speed water flow and reduce flooding

conservation - the management of a resource in such a way as to assure that it will continue to provide maximum benefit to humans over the log run

costal plain - level land with generally fine and fertile soils downstream of a piedmont and fall line, where tidal influence is felt in the rivers

costa - also called the costal vein, the major longitudinal vein forming the leading edge of the wing

cross vein - a short vein joining any two neighboring longitudinal veins

D

damselfly - order of Odonata, suborder Zygoptera, characterized by narrow wings, forewing
and hind-wing similar in shape held folded along the body at rest; eyes widely separated; small
and slim bodied

detritus - accumulated organic debris from dead organisms, a source of nutrients in a food chain

dimorphic - occurring in two distinct forms

dissolved oxygen - Oxygen gas molecules dissolved in water.  Fish and other aquatic organisms depend on dissolved oxygen for respiration therefore, the concentration of dissolved oxygen is a measure of water quality

distal - furthest away from the body

diversity - an ecological measure of the variety of organisms present in a habitat

dorsal - top of the odonate

dragonfly - order of Odonata, suborder Anisoptera; characterized by large broad wings, held
away from body when perched and flying; eyes touching in most species; large bodied

E

ecosystem - all the organisms in a particular region and the environment in which they live.  The elements of an ecosystem interact with each other in some way, and so depend on each other either directly or indirectly.

emerge - eclosion of the winged adult from the last larval stage

endemic species - a species that is restricted in its distribution to a particular locality or region

endophytic oviposition - laying eggs into plant tissue

environment - the place in which an organism lives, and the circumstances under which it lives

epiphytes - plants that live on the surface of other plants, especially the trunk and branches

estuary - a bay or river system open to the ocean at one end and receiving fresh water at the other.  In an estuary, fresh and salt water mix producing brackish water.

eutrophic - highly fertile and nutrient enriched

exophytic oviposition -  laying eggs onto water or land

extinction - the death of all individuals of a particular species

exuviae - the empty shells left behind after the adult emerges from the last larval stage. (technically, the shell left behind from any molt stage)

eyes - The individual facets of the compound eye are called the ommatidia.  The ommatidia are hexagonal in shape, so that all fit together in a honeycomb pattern to create the complete compound eye.  Most dragonflies have larger ommatidia on the upper surface of the eye, and small ones on the lower surface of the eye.  The larger lenses allow the dragonfly to see objects that are far away, and the smaller ones allow it to see objects that are near.

F

family - Each order of insects is divided into smaller groups called families.  The species within
a family are more similar and more closely related to each other than species in another
family in the same order.

femur - The largest and uppermost section of the leg.  It is the heaviest and is similar to the human thigh.  It is hairy or spiny for better gripping.

flight season - inclusive dates when an odonate is most apt to be seen

forewing - the wing closest to the head arising from the second thoracic segment

frons - The most visible part of the dragonfly's face.  Its coloration is relevant in dragonfly identification.

G

genus - members of a family related in structures and heredity that can be further
divided into species

gills - a respiratory structure through which oxygen is obtained

globular - rounded in shape

H

hamules - Hook like projections that are found under abdominal S2 on the male dragonfly.  Its function is to hold the females genitalia in place during mating.

head capsule - fused head sclerites that form a case

herbaceous - a plant with soft tissue that dies back to the ground every year

herbicide - a chemical used to kill or inhibit the growth of undesired plants

hip or coxs - This part connects the leg to the body.

humeral vein - a small cross-vein running from the costa to the sub-costa in the humeral region
of the wing

hyaline - means clear or transparent and is used to describe the wings of a dragonfly

hybrid - a plant or animal resulting from a cross between two closely related species that do not  normally cross

I

inferior anal appendages - "EPIPROCT" refers to the lower terminal appendage.

instar -  a molting or shedding of the larvae exoskeleton

J,K,L

labial mask - on odonata the part of the labium that covers part of the head

labium -  Lower lip that can be extended and retracted to capture and eat prey. The labium is folded under the head and thorax when it is not being used.  The labium can be extended to catch prey and retracted to direct the prey into the dragonfly's mouth where it is torn apart by slicing mandibles.  This action is done with such great speed that one rarely gets the opportunity to witness it.

labrum - This is the "upper lip" of the insects mouth-parts.  It also aids in the tearing up of food.

lamellae - leaf-like structure at the terminal end of a damselflies abdomen

larva -  immature stage of Odonata, larva, nymph, naiad are often used interchangeably
to describe the intermediate stage of the dragonflies life (between eggs and adult)

lateral - the side of the odonate

M

macrohabitat - a place where a lot of organisms live

mandibles - The mandibles consist of the upper and the lower lips surrounding the mouth.  The upper jaws being the (mandibulae) and the lower jaws being the (maxillae).  Mandibles are toothed and move from side to side tearing up prey.  The Greek word "Odonata" refers to the serrated teeth located on the insect's mandibles.

maxillae - the mouthparts that are located between the mandible and the lower labium

mentum - ventral plate on the ventral side of the head

mesonotum - dorsal surface of the second thoracic segment

metastemum - the ventral parts of the final thoracic segment

metatarsus - the last segment of the "foot"

mesothorax - This is the middle segment of the thorax.  It has one pair of wings and one pair of legs.

metathorax - This is the last segment of the thorax.  It has one pair of wings and one pair of legs.

microhabitat - a place where little organisms live

N

naiad - commonly used term meaning the same as nymph

nodus - the indentation in the costa vein

notum - dorsal surface of thoracic body segment

nymph - commonly used name for larva; newborn dragonfly

O

obelisk position - a posture with the abdomen raised nearly vertical to minimize exposure to the sun

occiput  - The back of the head between the vertex and the neck.  Head damage from mating usually occurs in this area.  The males EPIPROCT can accidentally punch holes in the females occiput during mating.  This is not an everyday occurrence, but on occasion will happen.  The dragonhunter is noted for this.

Odonata - the order in the animal kingdom of dragonflies and damselflies

odonate -  a common word for dragonfly/damselfly

oligotrophic - possibly nutrient poor, less fertile

oviposit -  to lay eggs

ovipositor - The external female genitalia used for egg laying found at the tip of the abdomen. It is located under abdominal S8-S10.  It is difficult to view this organ without having captured the insect and using magnification.  The shape of the ovipositor has relevance on how the eggs are to be laid.

P

palpal lobes - paired lobes on the distal end of the premenum in dragonflies and damselflies

paraprocts  - the innermost pair of anal appendages

parasite - living off of another organism while it is still alive

pesticide - a chemical used to kill pests.  Pesticides are further categorized according to the pest they are designed to kill - for example, herbicides kill plants, insecticides kill insects, fungicides kill fungi and so on

pools - distinct habitats within the stream where the velocity of the water is reduced and the depth of the water is greater than that of most of the stream area

posterior - toward the back or end of the odonate

posternal horn - a horn-like appendage found on the ventral side, located just behind the head capsule and just above where the first pair of legs connect to the thorax

predator - organisms that feed on animal matter

pronotum - a shield-like plate covering the top of the thorax

pro-thorax - This first segment is located at the front of the dragonfly's body; this small section connects the head to the body.  On the pro-thorax is the dragonfly's first pair of legs.  The pro-thorax also allows the dragonfly to keep equilibrium during flight.

proximal - nearest the body or base of a given part

pruinosity - a bluish or whitish powder which forms on the surface of mature dragonflies

pterostigm -  a shaded area on the upper and outer edge of the wing of damselflies

Q,R,S

respiratory tube - a large tube used to obtain air from the surface while an insect is submerged

riffles - Shallow, turbulent, swiftly flowing stretches of water that flow over partially or totally submerged rocks. This is where you can here the sound of the water moving

spiracle - an external opening along the body of insects used for air intake

spiracle plates - plates that are found on spiracles

stigma - a solid rectangular spot near the tip of the wing

superior anal appendages - "CERCI" refers to the upper and outer terminal appendage.  In conjunction with the shape of the interior appendage, species identification is made possible.

suture - a line in the body wall

T

tandem - a position  where the male and female are attached; usually seen during mating

tarsus - This includes the three segments and a claw on the end of the leg.  Together, these form the foot.

teneral - a stage of development following emergence; a newly emerged adult

terminal - referring to the posterior end of the body or the distal end of an appendage.

terminal  appendages - Commonly referred to as "CLASPERS"  in males.  The  appendages lay at the tip of the abdomen.  The males use the anal appendages to clasp the female behind the head or on the pro-thorax , keeping her in position while mating.  Each species will have its own unique set of anal appendages or "CLASPERS".  When identification is difficult, knowing the shape of these appendages may be the only field mark you can go by for correct identification.

tibia - This is the second section of the leg.  It is equivalent of the human shin.  It is hairy or spiny to grip and capture prey.

trachael branches - internal stem-like structures in insects.

tuberacles - small mound-like projections on the body

U,V

ventral - the underside of the organism

ventrolateral - running laterally along the ventral side of an insect.

W

watershed - may also be called a drainage basin, is the area in which all water, sediments, and dissolved materials flow or drain from the land into a common river, lake, or other body of water.
wetland - is a generic term for all the different kinds of wet habitats where the land is wet for some period of time each year but  not necessarily permanently wet.  Wetlands generally include swamps, marshes, bogs and similar areas.

wing pads - a developing wing

wing venation - refers to the pattern of veins in the wing

wing whirring - vibrating the wings rapidly to warm up

X,Y,Z

Zygoptera - suborder of odonata; specifically damselflies

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