Protura (Telsontails)
conical head, piercing mouthparts, lacks eyes and wingless, 12 segments in abdomen, .6-1.5mm
Collembola (Springtails)
wingless, long bodies, 4-6 abdominal segments, multicolored, tube protrudes from abdomen, microscopic
Diplura (diplurans)
1-segmented tarsi, chewing mouthparts, 2 cerci on head
Thysanura (Bristletails)
spindle shaped, flat bodies with 3 long, bristly tail like appendages
Ephemeroptera (Mayflies)
distinguished easily by their two large, triangular wings
Odonata (Dragonflies & damselflies)
two pairs of elongate membranous wings, compound eyes large, abdomen long and slender, antennae very short
Plecoptera (Stoneflies)
4 membranous wings, elongate, flattened, cerci present, long antennae, mouthparts chewing
Orthoptera (Grasshoppers & crickets)
usually 2 pairs of wings, antennae many-segmented, cerci present, has ovipositor, FW is long, narrow, and many veined
Blattodea (Roaches)
flattened oval bodies, long laid back antennae, wings (almost never used)
Isoptera (Termites)
small, soft-bodies, usually pale-colored, antennae generally short and thread- or bead-like
Dermaptera (Earwigs)
slender flattened bodies, large pincers at end
Mallophaga (Chewing lice)
bristly body, toothed mandibles, small compound eyes, head wider than thorax
Anoplura (Sucking lice)
flattened and wingless, sucking mouthparts, head narrower than thorax, claws
Thysanoptera (Thrips)
slender bodies, short antennae, short legs, feathery wings
Hemiptera (True bugs)
FW (front wing) thickened at base and membranous at tip, HW (hind) shorter than FW, wings held flat on body, tips of FW overlap, mouthparts sucking, antennae of 5 or fewer segments (long and conspicuous or short and concealed)
Homoptera (cicadas and more)
beak short and rising at back of head (different from Hemiptera), wings held rooflike over body, tarsi 1- to 3-segmented, antennae sometimes short and bristlike or sometimes long and threadlike
Neuroptera (lacewings, antlions)
FW and HW almost same size, four membranous wings, wings held rooflike over body at rest, wings with many veins, antennae long, cerci absent, mouthparts chewing
Coleoptera (beetles)
FW horny or leathery, FWs meet in straight line on back, HW membranous and are usually longer than FW, wings rarely absent or reduced, antennae usually with 11 segments (sometimes with 8-10), antennae variable in form
Mecoptera (Scorpionflies)
slender, soft bodies; long legs and elongated, snout like heads
Trichoptera (Caddisflies)
shaped or colored like certain moths, antennae long and threadlike, antennae usually long as body or longer, HW a little shorter than FW
Lepidoptera (Moths & Butterflies)
4 membranous wings, usually have proboscis in form of coiled tupe, wings covererd in scales
Diptera (True flies)
one pair of membranous wings (you can identify them instantly from this), have knoblike projections called haltares
Siphonaptera (Fleas)
laterally flattened abdomens, tough skin, enlarged coxae, mouthparts with 3 piercing stylets for blood sucking
Hymenoptera (Bees, Ants, Wasps, and more)
wings are sometimes present, FW a little larger than HW, antennae usually fairly long
Phasmatodea (walking sticks)
looks like a stick (honestly, this should be a given)
Mantodea (mantids)
triangular head, raptorial front legs, not to be mistaken for mantidflies (which have wings)
Psocoptera (book & bark lice)
prominent head, threadlike antennae, thin "neck", HW smaller than FW, FW not heavily veined
Megaloptera (dobsonflies)
large jaws, similar wing structure to Neuroptera (lacewings, antlions) although jaws may give it away, 3 ocelli, 5-segmented tarsi
Strepsiptera (twisted-wing parasite)
easily distinguished by unique shape of wings (although the picture does not reveal it)
Grylloblattodea (ice insect)
wingless, long cerci (5-8 seg), long antennae