A Pictorial Key to the Order of Adult Insects
winged wingless
(go to page 64)
front wings hardened, leathery or front wings membranous
parchmentlike at least at the base (go to page 61)
chewing sucking
mouthparts mouthparts
without with front wings leathery front wings of
pincer-like pincer-like at base and uniform texture
cerci cerci membranous at end
DERMAPTERA HOMOPTERA
HEMIPTERA (leafhoppers, planthoppers,
(earwigs) (true bugs) cicadas, spittlebugs)
front wings with A. front wings hard,
branched veins without veins
jumping insects walking insects
A. hind femur enlarged A. hind femur not enlarged
B. tarsi with four or B. tarsi with five segments
fewer segments COLEOPTERA
A (beetles)
B
A
ORTHOPTERA DICTYOPTERA
(crickets, katydids, (roaches, mantids,
grasshoppers) walkingsticks)
60
continued from key page 60
two wings four wings
wings with few or A. wings usually covered
no scales; without with scales
coiled proboscis B. mouthparts consist of
coiled proboscis
A. pronotum pronotum not
extended over extended over
abdomen abdomen A
B
A LEPIDOPTERA
(butterflies and moths)
very slender wing with no fringe of hairs, or if
fringe of hairs as long as present, not as long as
ORTHOPTERA wing is wide wing is wide
(pigmy grasshoppers)
THYSANOPTERA (go to page 62)
(thrips)
end of abdomen without end of abdomen with
noticeable appendages style or thread-like tail
A. with haltere-like B. with halteres A. style-like tail B. two or three
organs in front of wings behind wings thread-like tails
A
B
B
COLEOPTERA DIPTERA HOMOPTERA EPHEMEROPTERA
(male stylopids) (flies, mosquitoes, (male scales) (mayflies)
gnats, midges)
61
continued from key page 61
hind wings equal to or hind wings smaller
larger than front wings than front wings
(go to page 63)
no long abdominal appendages abdomen with two or
three thread-like tails
tarsi two or three segmented tarsi with more than three
segments (usually five)
EPHEMEROPTERA
(mayflies)
A. piercing-sucking B. chewing mouthparts
mouthparts
B
B. antennae as long as
body; wings and body
often with scales
A A. antennae shorter than
body; no noticeable scales
HOMOPTERA A
(cicadas, leafhoppers,
planthoppers, spittlebugs) B
HYMENOPTERA
(bees, wasps, ichneumons) TRICHOPTERA
(caddisflies)
PSOCOPTERA
(barklice, booklice)
62
continued from key page 62
mouthparts mouthparts at end of beak-like
close to eye structure some distance from eye
MECOPTERA
wings never held (scorpionflies)
flat over abdomen
B. antennae apparently wings held
A. bristle-like flat over abdomen
inconspicuous antennae with several segments
B
A
ODONATA
(dragonflies, damselflies)
hind wings with enlarged hind wings without enlarged
anal area folded fan-like; anal area folded fan-like;
wings tend to curl around wings do not tend to curl
the body lengthwise around the body lengthwise
NEUROPTERA
MEGALOPTERA (lacewings, mantispids,
(dobsonflies, fishflies, owlflies, antlions)
alderflies)
all legs of hind legs modified
walking type for jumping
ORTHOPTERA
(tree crickets)
A. cerci usually long; B. cerci short; with
more than eight segments two to eight segments
B
A
ISOPTERA
PLECOPTERA (termites)
(stoneflies) 63
continued from key page 60
antennae present antennae absent
legs present legs absent
head and thorax head and thorax
separate fused
DIPTERA
(louse flies, bat flies)
HOMOPTERA COLEOPTERA
(scales) (female stylopoids)
A. collophore present; both collophore and
B. spring-like organ usually present spring-like organ absent
B
long tail-like three tail-like
A appendages absent appendages present
COLLEMBOLA
(springtails)
body not flattened A. body flattened laterally
B. or dorsoventrally
A THYSANURA
(silverfish)
B
(go to page 66)
(go to page 65)
64
continued from key page 64
body flattened dorsoventrally body flattened laterally
sucking mouthparts no sucking mouthparts
externally visible externally visible
SIPHONAPTERA
A. antennae longer B. antennae shorter (fleas)
than head than head
A
B
antennae longer antennae shorter
than head than head
HEMIPTERA DIPTERA
(true bugs) (louse flies and bat flies)
A. tiny insects; tarsi with B. large insects; tarsi
two or three segments with five segments
A
PSOCOPTERA DICTYOPTERA
(booklice, barklice) (roaches, mantids, walkingsticks)
A. head wider than thorax at B. head narrower than thorax at
point of attachment to thorax point of attachment to thorax
A
B
MALLOPHAGA ANOPLURA
(biting lice) (sucking lice)
65
continued from key page 64
abdomen and thorax not abdomen and thorax
narrowly joined together narrowly joined together
A
body covered body not covered
with scales with scales
HYMENOPTERA
(ants)
tarsal claws tarsal claws
absent present
LEPIDOPTERA
(female cankerworm) piercing-sucking chewing
mouthparts mouthparts
THYSANOPTERA
(thrips)
cornicles absent A. cornicles usually
present
A
with distinct without distinct
head and eyes head and eyes
HOMOPTERA
(aphids)
HOMOPTERA
(female scales)
HEMIPTERA
(bed bugs)
abdominal forceps present; abdominal forceps absent
entire body rather hard (go to page 67)
and brown colored
DERMAPTERA
(earwigs)
66
continued from key page 66
A. mouthparts at end of beak-like mouthparts not elongated,
structure some distance from eye close to eyes
cerci present cerci absent
A
MECOPTERA
(scorpionflies) A. antennae longer B. antennae shorter
than one-third of than one-fourth of
body length body length
B
A
body leathery and body soft and
usually grey or pale colored
dark colored
PSOCOPTERA COLEOPTERA
ORTHOPTERA (barklice and booklice) (female stylopids)
(crickets)
three to five tarsal segments
A. basal segment of front tarsi about
same size as ones immediately following
ISOPTERA
(termites)
67
