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Glossary of Terms
A B C D E F G H I L M N O P Q R S T U V W


A
Abdomen
The last, and usually largest, of the three portions of an insects body. The abdomen does not have any true legs. It begins after the thorax. It usually is made up of anywhere from 8 - 11 segments.

Anal fan
A fan of setae (long hairs) on the end of the abdomen

Annuli
On a leech this is what appears to be a single segment. In actuality there are several annuli per body segment.

Antennae
Slender sensory appendages arising from the front of the head

Anterior
At or toward the front of the body

Anterolateral angles
Angles that are perpendicular to the body of the insect

Aperture
The opening in a snail shell where the snail's foot and head emerge

Apex
The end of an appendage opposite the point of attachment, the tip of an appendage

Apical
Pertaining to the apex; example - "apical setae" would be a hairlike structure on the tip of an appendage

Apicolateral
Lateral (to the sides) to the apex

Appendage
Any structure attached to the body

 
B
Basal
(base) point of attachment for an appendage to the body

Beak Ridge
The raised loops, bumps and ridges on the umbo.

Beak Ridges
The raised loops, bumps and ridges on the umbo.

Bifid
- forked

Bilobed
Having two lobes, usually referring to gills

Brackish
Salt content greater than that of fresh water

 
C
Carina
A low ridge

Carinate
Having one or more spiral ridges

Carnivore
Species that feeds on other organisms

Caudal
Toward the tail or posterior end of an organism

Caudal lamellae
Terminal gill filaments of the damselfly larvae (Zygoptera). Usually flat and broad

Cellulose
Plant cell material

Cerci
Appendage on terminal abdominal segment

Cercus
One cerci - an appendage on terminal abdominal segment

Chelate
A pincerlike exoskeleton at the end of an appendage

Chloride epithelia
Oval rings occuring on the abdomen of some Trichoptera

Clitellum
The segments on an annelid where the sexual pores are located. It secretes substances necessary for reproduction. It may be appear swollen.

Collectors
Species that are detrivores, herbivores, or both

Columella
In a spiraling gastropod shell it is the pillar located in the center of the coils.

Conispiral
To whorl towards the apex in a cone-shaped fashion

Convex
Mounded, a surface that curves outward

Coxa
The segment of a leg that is nearest the body

Crenulations
Small convex bumps

Crochet
Curved hooks that are found at the terminal end of prolegs

Cupule
Segment of an antennae

 
D
Dentes
An appendage found at or near the end of the abdomen in Collembola

Depositional
Bodies of water with fine sediment deposits such as water pools

Detritus
Dead and decomposing plant or animal material

Detrivores
Organisms that feed on dead and decomposing plant or animal material

Dextral
When viewing snail from the front, with the apex at the top, the aperture will be located on the right side.

Diatoms
A unicellular form of algae

Distal
At or near the outermost region of a structure, opposite of Basal

Dorsal
Top side of an organism

Dorsolateral
Towards the side of the dorsal surface

Dorsoventrally flattened
Flattened horizontally

 
E
Ecdysis
Molting of the old exoskeleton

Elongate lanceolate
Long and spearshaped in appearance

Elytra
The hardened fore wing of Coleoptera adults

Engulfers
Carnivores that attack prey and swallow it whole

Epipleuron
A body plate on the side of an adult beetle thorax

Erosional
Bodies of water with coarse sediment deposits such as riffles

 
F
Femur
Third major segment of the leg

Fibrils
Thin filamentous structures

Filiform
Threadlike, usually refers to the appearance of the antennae

Filterers
Organisms that feed on decomposing material, and plant material at the surface

Forewing
The wing closest to the head, arises from the second thoracic segment

Fossorial
Formed for or with the habitat of digging, usually used to described modified legs

 
G
Gatherers
Organisms that feed on decomposing material, and plant material at the bottom of the water body

Gills
A respiratory structure through which oxygen is obtained

Globular
Rounded in shape

Glossae
The median terminal lobe of the labium, usually located on the underside of the head

Gonopores
The genital pores on the ventral surface of leeches. Since leeches are hermaphrodites there is both a male and female pore. The male pore (black arrow) is closer to the oral sucker, the female pore (white arrow) is closer to the larger tail sucker.

 
H
Head capsule
Fused head sclerites that form a case

Hemelytra
Forewings of insects that are thicker at their base

Herbivore
Species that feed on plant material

Host
An organism that a parasite uses for its own advantage

 
I
Instar
Developmental stages of larval insects

Integument
Skin

Intertidal
Coastal area between low and high tide

 
L
Labial mask
On Odonata the part of the labium that covers part of the head

Labial palpi
A pair of segmented appendages arising from the lower lip (labium) of an insect's mouth

Labium
The lower lip of insects

Labral fans
A fan of setae found by the mouth of an organism

Labrum
The upper lip of an insects head

Lamellae
Leaflike structure at the terminal end of a damselflies abdomen

Lateral Teeth
Elongated teeth along hinge line of shell

Lentic
Still bodies of water such as lakes and ponds

Ligula
On the prementum, the small bump between the two palpal lobes, or a toothed plate found behind the dorsomental teeth in the Tanypodinae subfamily of Diptera.

Linear
Having an extended shape

Littoral
The near shore areas of ponds and lakes where rooted and emergent plants grow

Longitudinal
Along the length of the body

Lotic
Flowing bodies of water such as rivers and streams

 
M
Mandibles
One of the mouthparts located directly behind the upper lip, in insects with chewing type mouthparts they are usually sickle shaped and the main structures for ripping and tearing the food

Maxillae
The mouthparts that are located between the mandible and the lower labium

Mentum
A ventral plate on the ventral side of the head

Mesonotum
Dorsal surface of the second thoracic segment

Metacephalic rods
In Diptera an elongate sclerite which extends from the head into the prothorax

Metasternum
The ventral part of the final thoracic segment

Mucro
Terminal segment of the dentes

 
N
Nacre
Interior layer of shell.

Nocturnal
Organisms which are active at night

Nodal furrow
Line located on outer edge of wing

Notoplural sutures
Grooves on Coleoptera adults that are found on the ventral side of the notum

Notum
Dorsal surface of thoracic body segment

 
O
Omnivore
Species that feeds on both organisms and plants

Operculum
A plate-like structure attached to the foot of most Gastropods.

 
P
Pala (Palae)
The tarsal segment of a Corixid front leg

Palpal lobes
Paired lobes on the distal end of the premenum in dragonflies and damselflies (Odonata)

Paraglossae
Lateral terminal lobes of the labium

Paraprocts
Two protrusions that surround the anal opening from the rectal chamber

Parasitic
Living off of another organism while it is still alive

Pectinate
Having narrow parallel projections

Periostracum
The outside covering of the shell.

Periphyton
Any benthic plant growth

Planispiral
To whorl towards the apex in a flattened fashion

Plastrons
A permanent gas film held by the hairs of some insects while they are submerged

Postantennal organ
An organ found on some Collembola that is located behind the eyes and looks like a black dot

Posterior
At or near the rear of the body

Posternal horn
A horn-like appendage found on the ventral side of some Trichoptera, located just behind the head capsule and just above the where the first pair of legs connects to the thorax

Preapical
Occurring near the end of a structure

Predator
Organisms that feed on animal matter

Prehensile
Modified for grasping

Prementum
Distal segment of the labium in Odonata

Prolegs
Any appendage that acts like a leg but is not a leg; usually stubby, fleshy protuberances

Pronotum
Dorsal surface of the first thoracic segment

Prothorax
The first thoracic segment.

Pseudocardinal Teeth
Teeth located on anterior part of shell.

Pustules
A bump on the outside surface of a mussel shell.

 
Q
Quadrate
Square or rectangular in shape

 
R
Raptorial
Appendages which are modified for catching and holding prey

Respiration
Breathing

Respiratory tube
A long tube used to obtain air from the surface while and insect is submerged

 
S
Scavengers
Organisms that feed on dead animal material

Sclerite
A hardened body wall

Sclerotized
A portion of the body wall that has been hardened and is usually darker in color

Scrapers
Herbivorous insects

Scute
A fingernail-shaped, colored structure found on some leeches on their dorsal surface, near the anterior end.

Scutellum
The posterior division of the notum

Setae
Hairlike structures

Sinistral
When viewing the snail from the front, with the apex at the top, the aperture will be located on the left.

Spiracles
An external opening along the body of insects used for air intake

Spiracular plates
Plates that are found on spiracles

Spire
The part of the shell that spirals up to the apex, but doesn't include the last whorl of the shell.

Spurs
In Coleoptera larva a structure used to obtain oxygen from plants

Sternites
Ventral plate of an abdominal segment

Stipites
The segment of the maxilla just after the basal segment

Strigil
A structure, usually made up of rows of comb-like teeth, on the sixth dorsal abdominal segment of the male Corixid.

Stylet
Penlike

Subimagos
In Ephemeroptera the fully winged form that precedes adults

Sulcus
Shallow depression on outside of shell.

Suture
A line in the body wall

 
T
Tarsal claw
Claw located at the end of the tarsi

Tarsal formula
The number of segments of the tarsi, starting with the fore leg, then the middle leg, then the hind leg. For example, a tarsal formula of "5-5-4" means there are 5 segments in the fore leg's tarsi, 5 segments in the middle leg's tarsi, and 4 segments in the hind leg's tarsi.

The middle and hind legs of a 5-5-5 tarsal formula is shown in this photo.

Tarsi
The major leg segment furthest from the body; varies in number from 2 - 5 depending on the type of insect; they connect to the tibia and may have one or two claws on the end (tarsi is plural, tarsus is singular)

Tarsus
The leg segment furthest from the body; vary in number from 2 - 5 depending on the type of insect; they connect to the tibia and may have one or two claws on the end (tarsus is singular, tarsi is plural)

Tergite
Dorsal plates of the abdomen

Terminal
Referring to the posterior end of the body or the distal end of an appendage

Terminal filaments
Long and slender rod-like structure on the final abdominal segment

Terrestrial
Organisms that are primarily found on land

Thorax
Second major body segment of an insect

Tibia
The fourth segment of an insect leg

Tolerance Value
A value from 0 through 10 rating an organism's tolerance to poor water quality.

Intolerant organisms are unable to survive poor water conditions. They have low values like 0, 1, or 2. Tolerant organisms will live in water of poor quality. Tolerant organisms have high values like 9 or 10.

Tracheal branches
Internal stemlike structures in insects

Trochantin
An appendage in Trichoptera larvae located anteriorly at the base of the fore leg

Trophic
Position in the food chain in terms of how nutrients are acquired

Tuberacles
Small mound-like projection on the body

 
U
Umbilicus
An open area at the center of the spiral of a snail shell. It is visible from underneath the shell when present.

 
V
Ventral
Bottom side of an organism

Ventrolateral
Running laterally along the ventral side of an insect

 
W
Wing pads
A developing wing

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