VCSU Macro-Invertabrate Lab

Glossary of Terms

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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.
A fan of setae (long hairs) on the end of the abdomen
On a leech this is what appears to be a single segment. In actuality there are several annuli per body segment.
Slender sensory appendages arising from the front of the head
At or toward the front of the body
Angles that are perpendicular to the body of the insect
The opening in a snail shell where the snail's foot and head emerge
The end of an appendage opposite the point of attachment, the tip of an appendage
Pertaining to the apex; example - "apical setae" would be a hairlike structure on the tip of an appendage
Lateral (to the sides) to the apex
Any structure attached to the body


(base) point of attachment for an appendage to the body
The raised loops, bumps and ridges on the umbo.
The raised loops, bumps and ridges on the umbo.
- forked
Having two lobes, usually referring to gills
Salt content greater than that of fresh water


A low ridge
Having one or more spiral ridges
Species that feeds on other organisms
Toward the tail or posterior end of an organism
Terminal gill filaments of the damselfly larvae (Zygoptera). Usually flat and broad
Plant cell material
Appendage on terminal abdominal segment
One cerci - an appendage on terminal abdominal segment
A pincerlike exoskeleton at the end of an appendage
Oval rings occuring on the abdomen of some Trichoptera
The segments on an annelid where the sexual pores are located. It secretes substances necessary for reproduction. It may be appear swollen.
Species that are detrivores, herbivores, or both
In a spiraling gastropod shell it is the pillar located in the center of the coils.
To whorl towards the apex in a cone-shaped fashion
Mounded, a surface that curves outward
The segment of a leg that is nearest the body
Small convex bumps
Curved hooks that are found at the terminal end of prolegs
Segment of an antennae


An appendage found at or near the end of the abdomen in Collembola
Bodies of water with fine sediment deposits such as water pools
Dead and decomposing plant or animal material
Organisms that feed on dead and decomposing plant or animal material
When viewing snail from the front, with the apex at the top, the aperture will be located on the right side.
A unicellular form of algae
At or near the outermost region of a structure, opposite of Basal
Top side of an organism
Towards the side of the dorsal surface
Flattened horizontally


Molting of the old exoskeleton
Long and spearshaped in appearance
The hardened fore wing of Coleoptera adults
Carnivores that attack prey and swallow it whole
A body plate on the side of an adult beetle thorax
Bodies of water with coarse sediment deposits such as riffles


Third major segment of the leg
Thin filamentous structures
Threadlike, usually refers to the appearance of the antennae
Organisms that feed on decomposing material, and plant material at the surface
The wing closest to the head, arises from the second thoracic segment
Formed for or with the habitat of digging, usually used to described modified legs


Organisms that feed on decomposing material, and plant material at the bottom of the water body
A respiratory structure through which oxygen is obtained
Rounded in shape
The median terminal lobe of the labium, usually located on the underside of the head
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.


Fused head sclerites that form a case
Forewings of insects that are thicker at their base
Species that feed on plant material
An organism that a parasite uses for its own advantage


Developmental stages of larval insects
Coastal area between low and high tide


On Odonata the part of the labium that covers part of the head
A pair of segmented appendages arising from the lower lip (labium) of an insect's mouth
The lower lip of insects
A fan of setae found by the mouth of an organism
The upper lip of an insects head
Leaflike structure at the terminal end of a damselflies abdomen
Elongated teeth along hinge line of shell
Still bodies of water such as lakes and ponds
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.
Having an extended shape
The near shore areas of ponds and lakes where rooted and emergent plants grow
Along the length of the body
Flowing bodies of water such as rivers and streams


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
The mouthparts that are located between the mandible and the lower labium
A ventral plate on the ventral side of the head
Dorsal surface of the second thoracic segment
In Diptera an elongate sclerite which extends from the head into the prothorax
The ventral part of the final thoracic segment
Terminal segment of the dentes


Interior layer of shell.
Organisms which are active at night
Line located on outer edge of wing
Grooves on Coleoptera adults that are found on the ventral side of the notum
Dorsal surface of thoracic body segment


Species that feeds on both organisms and plants
A plate-like structure attached to the foot of most Gastropods.


The tarsal segment of a Corixid front leg
Paired lobes on the distal end of the premenum in dragonflies and damselflies (Odonata)
Paired appendages attached to certain mouthparts of the insect. Usually visible on the underside of the head.
Lateral terminal lobes of the labium
Two protrusions that surround the anal opening from the rectal chamber
Living off of another organism while it is still alive
Having narrow parallel projections
The outside covering of the shell.
Any benthic plant growth
To whorl towards the apex in a flattened fashion
A permanent gas film held by the hairs of some insects while they are submerged
An organ found on some Collembola that is located behind the eyes and looks like a black dot
At or near the rear of the body
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
Occurring near the end of a structure
Organisms that feed on animal matter
Modified for grasping
Distal segment of the labium in Odonata
Any appendage that acts like a leg but is not a leg; usually stubby, fleshy protuberances
Dorsal surface of the first thoracic segment
The first thoracic segment.
Teeth located on anterior part of shell.
A bump on the outside surface of a mussel shell.


Square or rectangular in shape


Appendages which are modified for catching and holding prey
A long tube used to obtain air from the surface while and insect is submerged


Organisms that feed on dead animal material
A hardened body wall
A portion of the body wall that has been hardened and is usually darker in color
Herbivorous insects
A fingernail-shaped, colored structure found on some leeches on their dorsal surface, near the anterior end.
The posterior division of the notum
Hairlike structures
When viewing the snail from the front, with the apex at the top, the aperture will be located on the left.
An external opening along the body of insects used for air intake
Plates that are found on spiracles
The part of the shell that spirals up to the apex, but doesn't include the last whorl of the shell.
In Coleoptera larva a structure used to obtain oxygen from plants
Ventral plate of an abdominal segment
The segment of the maxilla just after the basal segment
A structure, usually made up of rows of comb-like teeth, on the sixth dorsal abdominal segment of the male Corixid.
In Ephemeroptera the fully winged form that precedes adults
Shallow depression on outside of shell.
A line in the body wall


Claw located at the end of the tarsi
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.
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)
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)
Dorsal plates of the abdomen
Referring to the posterior end of the body or the distal end of an appendage
Long and slender rod-like structure on the final abdominal segment
Organisms that are primarily found on land
Second major body segment of an insect
The fourth segment of an insect leg
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.
Internal stemlike structures in insects
An appendage in Trichoptera larvae located anteriorly at the base of the fore leg
Position in the food chain in terms of how nutrients are acquired
Small mound-like projection on the body


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


Bottom side of an organism
Running laterally along the ventral side of an insect


A developing wing

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