PHYLUM
CLASS
ORDER
FAMILY
GENUS
CLASS
ORDER
FAMILY
GENUS
ORDER
FAMILY
GENUS
GENUS
FAMILY
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
FAMILY
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
FAMILY
GENUS
GENUS
GENUS
GENUS
GENUS
FAMILY
GENUS
FAMILY
GENUS
GENUS
FAMILY
GENUS
GENUS
GENUS
GENUS
GENUS
FAMILY
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
FAMILY
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
GENUS
ORDER
FAMILY
GENUS
FAMILY
GENUS
FAMILY
GENUS
CLASS
ORDER
FAMILY
GENUS
FAMILY
GENUS
GENUS
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
accessory
Usually used to describe a small secondary structure. For example an accessory flagellum refers to a small flagellum attached to the antenna, or an accessory hook often refers to a small hook protruding from a larger anal hook.
anal division
the last abdominal "segment" in larval Diptera (that actually consists of several segments).
anal proleg
Proleg bearing hooks and located on the last segment of the abdomen, usually paired
anteapical
before the apex, ie. anteapical claws have the claw inserted basal to the tip of the tarsus.
anterolateral
adjective for a feature on the sides of the anterior (front) part of a structure; there are many other such combined-positioned adjectives.
apex
the most distal point of an object. Plural form is apices.
apicolateral
toward the apex and toward the side.
basal
the part of an appendage that is near the body.
benthic
pertaining to the bottom of a permanent body of water.
biforous
with two openings.
bilamellate
having or divided into 2 plates.
biofilm
fungus, algae, and bacteria that forms a slippery, inconspicuous film over rocks and other substrates.
bowed
bent or curved.
brackish
refers to slightly salty water, such as in an estuary or salt marsh.
burrower
an organism that lives in the sediments of streams and lakes.
carina
a ridge, or keel. Plural form is carinae.
caudal
pertaining to the posterior end of the abdomen.
caudal filament
tail, when there is only one, or the middle tail when there are three (the other two being cerci).
cerci
pair of tails
chelate
pincer-like.
chloride epithelia
region of the outer body with specialized cells to extract ions from the water; usually indistinguishable visually, but defined in some caddisfly larvae by a fine dark line surrounding the margins.
claval furrow
in Hemiptera, a large furrow on the forewing separating the clavas (posterior when the wings are spread) and the ebolium (anterior when the wings are spread).
clavate
club-like, enlarged at the distal end.
clavus
in Hemiptera, when the wings are spread, it is the part of the wing posterior to the claval furrow; the wing minus the ebolium. 
climber
an organism that lives on plants or debris underwater with adaptations for moving along stems and roots.
clinger
An organism that attaches to surfaces in stream riffles; typically has adaptations (such as claws) or behaviors (like retreat construction) to live in these habitats.
clypeus
the front part of an insect's head below the frons to which the labrum is attached anteriorly.
collector-filterer
organisms that filter out particles suspended in water to eat.
collector-gatherer
organisms that feed on deposited sediments.
collum
neck, posterior-most portion of the head in beetle larvae.
compound eye
an eye composed of several visual units, called ommatidia.
compressed
adjective for a flattened shape taller than wide.
concave
curved inward, caved in.
conspicuous
easily visible.
convex
curved outward, rounded.
coxa
the leg segment nearest the body. Plural form is coxae.
crenation
rounded projection.
crenulated
scalloped, having a margin with repeated indentations and rounded projections.
cupule
the hairless, cup-shaped sixth segment of a water scavenger beetle's antennae.
deciduous
falling off at certain periods. For example, this term is used to describe the gills of nymphs in the family Heptageniidae (Ephemeroptera), which fall off easily when handled.
denticle
small tooth. [image]
diatom
specimen of a major group of microalgae.
digitiform
finger-like.
dilated
enlarged, widely opened.
distal
the part of an appendage that is furthest away from the body.
diver
an organism that swims by rowing with its hind legs in lentic and lotic habitats; typically comes to surface of water for oxygen.
dorsal
on or of the upper surface.
dorsoventral
adjective for a flattened shape wider than tall; depressed.
dun
common name for a subimago mayfly.
ecdysial line
any line where sclerites of the exoskeleton will separate during the molting process. These are found mostly on the midline of the top or underside of the head and on the midline of the top of the thorax.
eclosion
when a larva hatches from an egg.
elytron
hardened shell-like forewings of a beetle that cover the hind wings. Plural form is elytra.
embolium
in Hemiptera, when the wings are spread, it is the part of the wing anterior to the claval furrow. If the wings are closed, it is the part of the wings nearest the lateral margin, not including the clavus. 
engulfer-predator
an organism that attacks and eats whole animals or parts.
femora
the thigh. This is the second most basal leg segment, after the coxa.
fibrilliform
thread-like.
fibrils
thread-like protuberances.
filamentous
with thread-like filaments.
filiform
adjective for fine or thread-like.
filterers
insects that feed by sifting suspended organic matter (including detritus, diatoms, algae, and sometimes meiofauna), from the water.
flange
tall ridge.
foreleg
prothoracic leg; a leg on the first thoracic segment.
foretrochantin
a part of a propleuron of a caddisfly that projects forward from the base of a foreleg.
fossorial
adjective for legs and other structures used in digging.
foveate
punctate, or pitted, with evenly distributed indentations.
frontal process
In mayflies of the family Ephemeridae, when looking dorsally, a cuticular lobe projecting forward from the anteriormost margin of the face.
frontoclypeus
the face or front middle region of the head, usually defined by a pair of curved lines extending forward from the anterior end of the median dorsal ecdysial line.
fusiform
spindle-shaped or football-shaped, tapered at both ends.
gena
cheek. Plural form is genae.
gill
respiratory organ; an extension of the body wall with many tracheae, variously either single and thread-like, multi-branched, flat, forked, etc.
glabrous
without hair/setae.
glossae
part of the mouth parts/labrum, pair of lobes used much like a tongue. Smaller, and just inside of paraglossae. See image. [image]
gula
in prognathous insects, the fused lower ends of the postocciput forming a plate on the underside of the insect's head.
hemimetabolist
a type of insect where the life cycle includes egg, larval, and adult stages, but lacks a pupal stage.
hind leg
metathoracic leg; a leg on the third thoracic segment.
holometabolous
with 4 life stages (with "complete metamorphosis"): egg, larva, pupa, adult.
hydrofuge
water repelling.
hydrofuge pile
water-repelling hairs.
hydrophilic
water-loving; attracted to water.
hydrophobic
water-repelling.
hygropetric
life that needs to live on a thin film of water.
hypognathous
having the head vertical and the mouth facing downward. 
hypostoma
region of the lower genae (cheeks) behind the mandible.
hypostomal groove
depression on the lower genae (cheeks) behind the mandible.
imago
an adult insect.
inconspicuous
difficult to see.
instar
body form during any of several periods between larval molts.
intermediate teeth
looking at a Simuliid larva, this refers to the small teeth between the larger teeth on the hypostoma
interocular
between the eyes.
intersegmental
between segments.
intersegmental fold
where the membranous tissue bubbles up to fill the space between segments. In some caddisfly larvae this looks like a “fat roll.”
keel
a ridge, or carina.
labial mask
extendable mask-like mouth part of a dragonfly or damselfly nymph, used to capture prey. 
labium
lower lip. [image]
labrum
upper lip, touching the clypeus in front of the mouth. [image]
lacinia
inside edge of maxilla. [image]
lamella
a flat, plate-like structure. Plural form is lamellae.
lamelliform
plate-like or flap-like.
lanceolate
lance-like or long and skinny.
larva
immature feeding stage of an insect. Plural form is larvae. Latin=terrifying mask.
lateral
pertaining to, or attached to, the side.
leaf pack
accumulations of leaves and other coarse particulate matter in front of or behind obstructions in the water flow, such as logs.
lentic
describes an animal that lives in still, low oxygenated water.
lentic-profundal
zone of a standing body of water where fine sediments from shallower parts of the lake mix with organic matter from deeper reaches of the lake.
ligula
the combination of the glossae and paraglossae, used like a tongue.
littoral
the shore of a body of water.
lotic
describes an animal that lives in flowing, highly oxygenated water.
lotic-depositional
running-water pools and margins with fine sediments, some vascular plants growing in those sediments, and leaf litter forming the majority of detritus.
lotic-erosional
running-water riffles with coarse sediments, some plants growing in those coarse sediments, and leaf packs and woody debris serving as the majority of detritus. 
maxilla
second pair of jaws. Plural form is maxillae.
median
in the middle, centered.
meiofauna
small animals, usually small invertebrates.
membranous
thin and more or less transparent.
mentum
 part of the base of the labium, also referred to as the anterior ventral apotome. [image]
mesal
on the midline of the back or underside of the animal.
meso-
prefix referring to a structure on the second thoracic segment behind the head.
mesonotum
dorsal side of the second thoracic segment.
mesopleuron
the lateral portion of the middle thoracic segment.
mesosternum
bottom side of the second thoracic segment. 
meta-
prefix referring to a structure on the third thoracic segment behind the head.
metacoxa
basal segment of a hind leg. Plural is metacoxae.
metanotum
top side of the third thoracic segment.
metasternum
bottom side of the third thoracic segment.
mola
roughened grinding area at base of each mandible of some insects. [image]
nasale
fused frons, clypeus, and labrum; anteriormost margin of the face in beetle larvae.
neuston
small organisms that live in the surface layers of water.
neustonic
of or relating to the habit of living in the surface layers of water.
notopleural
adjective referring to the region on each side at the lateral edge of a notum.
notum
a hard plate on the top of a thoracic segment of an insect or other arthropod.  Plural form is nota.
nymph
larval or immature feeding stage of an insect, usually of non-holometabolous insects.
occiput
the part of the top of the head that is closest to the body.
ocellus
in adult insects, a simple eye consisting of a single beadlike lens; in holometabolous larvae, simple eyes that make up the lateral eye-groups (also referred to as stemma). Plural form is ocelli.
operculate gill
a gill that covers the gill(s) on the next segment(s); usually these types of gills are flat and positioned on the dorsal (top) side of the abdomen.
operculum
a lid or cover. Plural form is opercula.
palmate
like the palm of the hand with processes stemming from a singular point, used in reference to gill venation.
palp
The paired and segmented appendages around the mouth arising from maxillae (one palp on each maxilla) and the labium (one pair); maxillary palps are the larger pair. Plural form is palps. See also palpus. [image]
palpus
The paired and segmented appendages around the mouth arising from maxillae (one palpus on each maxilla) and the labium (one pair); maxillary palpi are the larger pair. Plural form is palpi. See also palp.
paraglossae
part of the mouth parts/ labrum, pair of lobes used much like a tongue. Larger and just outside of glossae. See image. [image]
paralateral teeth
looking at a Simuliid larva, as you move away from the center of the hypostoma, paralateral teeth refers to any smaller teeth just beyond the large lateral teeth.
patella
this is the knee, the leg segment found between the femora and tibia in some insects, but is usually absent.
pectinate
adjective for a structure with many teeth, like a comb.
percher
style of flight seen in some Odonates, where the dragonfly frequently lands and rests (perches) during flight. 
periphyton
fungus, algae, and bacteria that forms a slippery, inconspicuous film over rocks and other substrates.
petiolate
stalk-like, narrow, long and skinny.
piercer-herbivore
organism that pierces through vegetation and sucks plant fluids.
piercer-predator
Organism that consumes prey by piercing through its tissues and sucking fluids.
pilosity
fine long hairs.
pinnate
feathered; plumed; winged.  Used in reference to gill venation that appears feather-like.
planktonic
organisms drifting or swimming with water movement.
plastron
thin film of air permanently held on the surface of the body by a dense pile of microscopic spines.
pleuron
side of a thoracic or abdominal segment. Plural form is pleura.
plumose
plume-like or feather-like.
postgenal cleft
split located behind the cheeks (genae).
postmentum
posterior sclerite(s) on the underside of the head behind the prementum, sometimes divided into an anterior mentum and posterior submentum.
prementum
anterior sclerite on the underside of the head supporting labial palps, glossae and paraglossae; also called labiostipites.
primary hairs
hairs on the head, thorax, or abdomen.
pro-
prefix referring to a structure on the first thoracic segment behind the head.
proleg
fleshy unsegmented nub, often paired, used for movement (e.g., on the abdomen of most caterpillars and some flies; on the thorax of some fly larvae).
pronotum
the top part of the first thoracic segment.
prosternum
the bottom part of the first thoracic segment.
pubescence
clothed with soft, fine hairs.
pupa
non-feeding life stage between larva and adult. Plural form is pupae.
raptorial
adapted for grabbing prey.
riffle
fast-flowing, turbulent water flowing over rocks or other solid objects on the stream bottom.
rostrum
beak, or elongate mouth part as in Coleoptera: Curculionidae (Weevels) or Hemiptera (true bugs).
sa1, sa2, sa3
sa = setal area of a thoracic or abdominal segment, often marked by a sclerite or patch of setae--See image.
scalloped
crenulated, having a margin with repeated indentations and rounded projections.
sclerite
hardened plate, usually looks shiny.
sclerotized
hardened and usually darkened.
scraper-grazer
organism that feeds on algae attached to organic and mineral surfaces.
scrapers
refers to insects that graze on attached biofilm/periphyton on rocks and other substrates.
scutellum
in Hemiptera, the triangular part of the mesothorax placed between the bases of the hemelytra, but in some groups partially or fully overlapping them.
secondary hairs
randomly occurring hairs.
semioperculate gill
a gill that only partially covers the gill(s) on the next segment(s).
seta
hair. Plural form is setae.
setose
hairy; with setae.
shredder-detritivore
organism that eats by chewing coarse particulate organic matter.
shredder-gouger
organism that eats by digging through wood.
shredder-herbivore
organism that eats living aquatic plants and algae by chewing and mining.
skimmer
a style of flight seen in some Odonates where the dragonfly skims along the surface of the water, or more generally, they don't land frequently and seem to constantly be in flight while hunting.
spatulate
broad at the end, like a spatula.
spicule
tiny spike on an insect’s surface.
spinner
common name for an adult mayfly (Ephemeroptera); imago.
spinneret
small tube-shaped appendage that exudes silk threads, especially seen in spiders and larval Trichoptera and Lepidoptera. In larvae, this is typically located on the labium (lower lip) of an individual.
spinulate
severall small spines, spine-like processes, or hairs
spinule
small spine. Plural form is spinules.
spinulose
severall small spines, spine-like processes, or hairs.
spiracle
external opening of the tracheal system; can look like a small pore on an insect's body.
spiracular disc
In amphipneustic and metapneustic Diptera larvae, disclike area with respiratory openings on the last segment.
sprawler
live on the surface of submerged objects or sediment; adapted to keep sediment off of themselves and remain on top of the substrate.
stemma
simple eyes that make up the lateral eye-groups in holometabolous larvae. Plural form is stemmata. Similar to ocelli, but in clusters of more than 3; usually present in larvae of holomotabolus insects.
stemmata
simple eyes, similar to ocelli, but in clusters of more than 3; usually present in larvae of holomotabolus insects.
sternite
a hard plate on the underside of a thoracic or abdominal segment of an insect or other arthropod.
stipes
the second segment of the maxillae (second set of jaws). The lacinia, galea, and maxillary palps arise from the stipes.
stria
a fine impressed line running lengthwise over the elytra of adult Coleoptera. Plural form is striae.
subimago
also known as a dun (common name). A life stage unique to the Ephemeroptera; a developmental stage between larval and adult stages in which the wings have developed but the genitalia have not. In this stage the wings appear clouded (unlike the glossy appearance in the adults). The mayflies leave the water as subimagos, fly to a safe location, and then molt one more time to become an adult.
submental
below the mentum.
submentum
posterior sclerite of a divided postmentum on the underside of the head.
sulcus
groove with purely functional origin; i.e., any other groove on the body that is not a suture, such as those used for ecdysis or muscle attachment. Plural form is sulci.
suture
groove marking the line of fusion of 2 formerly distinct plates.
swimmer
organisms that are adapted to fishlike swimming; often cling to submerged objects and plants between bursts of swimming.
tarsal claw
hook (toenail) at the end of a tarsus (foot); one or two may be present.
tarsal formula
the number of tarsal segments of each leg pair listed in order; ie. # of tarsal segments of foreleg, middle leg, hind leg.
tarsungulus
fused tarsus and claw.
tarsus
foot, most distal leg region (last part of a leg before the claw), often divided into subsegments. Plural form is tarsi.
tergite
a hard plate on the top of an abdominal segment of an insect or other arthropod.
tergum
dorsal side of a given abdominal segment. Plural form is terga.
thoracic
belonging to the thorax.
tibia
tibia, shin or calf - not counting the claw, this is the second-most distal segment of the leg, proximal to the tarsus. Plural form is tibiae.
tomentum
short, wooly, rough hair.
trachea
internal tubes filled with air that the insect uses for breathing. Sometimes visible through the gills of aquatic insects, vein-like in appearance. 
transverse
broader than long, extending across something.
trochantin
hard structure on front of base of front leg of a caddisfly, usually more or less triangular and pointed apically, sometimes forked or hatchet-shaped.
tubercles
rounded projections.
urogomphus
in larval Coleoptera, paired processes extending from the end of the ninth abdominal tergum that are either jointed and moveable with muscles, or unjointed and immovable. Plural form is urogomphi.
vascular hydrophytes
aquatic plants with tissues that can conduct water and other nutrients.
ventral
the underside of the animal, opposite of dorsal.
ventral apotome
triangular or rectangular sclerite between the genae on the ventral side of the head capsule of some caddisflies; sometimes divided by a single ventral ecdysal line where the genae meet in the middle, creating two smaller apotomes on either end of the suture, the anterior and posterior apotomes. [image]
wing pads
undeveloped and encased wings located behind the thorax of hemimetabolous insect nymphs, including mayflies, stoneflies, true bugs, and dragonflies.