Stink Bugs, Shield Bugs, and the rest of the insects on this page are all members of Pentatomomorpha, an infraorder of True Bugs (order Hemiptera). They are most closely related to Cimicomorpha, the Assassin Bugs and Capsin Bugs, and are somewhat more distantly related to Water Bugs and Water Striders.
Like all true bugs, the members of this group have piercing/sucking mouthparts. Most of these species use those mouthparts to suck plant sap, though a few are carnivorous and feed on other insects. They have a hard exoskeleton.
Note on identifications – in the “nymph” stage, many of these bugs go through several color phases quite different from those of their parents. As it would be too cumbersome to show every possible nymph stage for every species, I’ve chosen to only focus on adults. If you wish to identify a nymph you will have to look up the individual species or post to Bugguide or iNaturalist.
Stink Bugs ( Pentatomidae)
Members of the family Pentatomidae are famous for the foul odor they emit when disturbed. They tend to have a shield-shaped body and a five-segment antennae. While most species suck plant juices, a few are predatory.
Green Stink Bug ( – To 0.75″. Green with black dots on the back edge of abdomen. Tiny pale dots at front of scutellum (the segment in the middle). Found in forest edges, orchards, and crops/gardens. (photo © ) Chinavia hilaris Howard Bruner)
Uhler’s Stink Bug (– To 0.65″. Green, with 3 white/cream raised marks at front of scutellum and one at the apex. The embolium (edge of wing) is narrower than in rossiana. Found in crops and fields. (photo © Chlorochroa uhleri) Robby Deans)
Pacific Stink Bug ( – To 0.6″. Green. Three white marks on scutellum small or missing altogether. Similar to Conchuela Bug and may need to examine genitalia to distinguish. Found on bushes and crops. (photo © Chlorochroa rossiana) Kurt Steinbach)
– To 0.75″. Green in north (brown in south), lacks spots at front of scutellum and apex is yellow/orange (red in south), as is edge of abdomen. Found on crops. (photo © Conchuela Bug ( Chlorochroa ligata) Don Henise)
– 0.4″. Green with red “shoulders” and sometimes a red band across the pronotum. Lacks black spots on the lower sides of abdomen. Found on crops and orchards. (photo © Western Red-shouldered Stink Bug ( Thyanta pallidovirens) Keir Morse)
– To 0.4″. Front of pronotum and scutellum are green, rest of back is reddish-brown. Exoskeleton pitted throughout. Found on trees (including conifers) and bushes. (photo © Green Burgundy Stink Bug ( Banasa dimidiate) Christopher)
Muddy Stink Bug (– To 0.45″. Muddy brown, grayish-brown or black, with tan or greenish scutellum. Clearly pitted throughout. Four rows of dark blotches on bottom. Found on cedar and cypress. (photo © Banasa sordida) James Bailey)
Gloomy Stink Bug (– To 0.4″. Uniformly dark brown or black except for bands at back edge of abdomen. Shape is especially round. Found on holly, blackberry, and hawthorn. (photo © Holcostethus tristis) Rudyard)
– To 0.35″. A squat species, mottled grayish-brown. Short head, shoulders rounded. Light apex on scutellum. Abdomen banded at edge. Found on holly, blackberry, and hawthorn. (photo © Short Stink Bug ( ) Holcostethus abbreviatus James Bailey)
Yellow-edged Stink Bug ( -To 0.35″. Similar to Short Stink Bug but black markings on edge of abdomen do not reach edge. Found in weedy fields and gardens. (photo © Holcostethus limbolarius) Sam Kieschnick)
-To 0.25″. Slender oval shape. Gray-brown or yellowish-brown with pale line down middle and on both sides. Found on grasses and oats. (photo © Wavy Brown Stink Bug ( ) Neottiglossa undata corndog)
– To 0.25″. Similar to Wavy Brown Stink Bug but with darker markings and even more narrow body. Head large with concave center. Found on grasses and oats. (photo © Swollen-faced Stink Bug ( ) Neottiglossa tumidifrons Alex Bairstow)
– To 0.5″. Mottled tan to brown with sharp “shoulders” of the pronotum. A long spine on the underbelly reaches between the hind legs. Eats caterpillars and beetle larvae. (photo © Spined Soldier Bug ( ) Podisus maculiventris Chloe and Trevor)
– To 0.4″. Mottled tan to brown with sharp “shoulders”. Spine on abdomen is shorter or missing completely. Feeds on caterpillars and other insects. Found on trees. (photo © Short-spined Soldier Bug ( ) Podisus brevispinus Jason Michael Crockwell)
Gilded Predatory Stink Bug (– To 0.7″. Brownish-orange, may have black marking. Larger than ) Apoecilus bracteatus Podisus species with thorax sloped evenly to pointed shoulders. Lacks dark streak at end of abdomen. (photo © Jean-Francois Roch)
One-spotted Stink Bug (– To 0.6″. Yellowish-brown to brownish-gray. Antennae dark on final two segments. Pointed “shoulders”. Apex of scutellum is light. Distinct black spot on genitalia below. Found on trees and vines. (photo © Euschistus variolarius) Jason Michael Crockwell)
– To 0.6″. Tan to grayish-yellow. Antennae dark on final two segments. Shoulders only somewhat pointed. Apex of scutellum sometimes light. Found on weeds, crops, shrubs and trees. (photo © Brown Stink Bug ( ) Euschistus servus Chloe and Trevor)
Consperse Stink Bug (– To 0.5″. Tan to brownish gray. Antennae dark only on final segment. Shoulders somewhat pointed and slightly serrated in front. Flatter and broader than Brown Stink Bug. Found on trees and vines. (photo © Euschistus conspersus) Thomas Barbin)
Small Stink Bug (– To 0.2″. Round and tiny. Speckled brown or copper, sometimes with light band at front of pronotum. Three light spots at front of scutellum. Found on berry bushes. (photo © Cosmopepla intergressa) Chloe and Trevor)
– 0.2-0.3″. Black, back of pronotum is red-to-orange with two black spots. Tip of scutellum lined in cream. Found on hedge nettle and columbine. (photo © Hedge Nettle Stink Bug ( ) Cosmopepla conspicillaris Jesse Rorabough)
– 0.2″. Similar to Hedge Nettle Stink Bug but lacks cream-colored line on scutellum. Black spots less pronounced. Found on California Figwort, columbine, and thimbleberry. (photo © Figwort Stink Bug ( ) Cosmopepla uhleri Don Loarie)
Twice-stabbed Stink Bug (– To 0.25″. Black with red or yellow line across pronotum, short line crossing it, and a pair of marks near the end of the scutellum. Found on mint, asparagus, milkweed, and many other plants. (photo © Cosmopepla lintneriana) Noah Strycker)
– To 0.45″. Black. Front of pronotum is red with two large black spots. Scutellum lined in red. A predatory species that eats Colorado Potato Beetles. (photo © Two-spotted Stink Bug ( ) Perillus bioculatus katunchik)
Blue Shield Bug (– To 0.35″. Metallic blue-green. Feeds on beetle grubs and caterpillars as well as plants. Found on low vegetation in fields and forest edges. (photo © ) Zicrona caerulea David Renoult) Shield Bugs (
Though the name “Shield Bug” is used for many related bugs, the family
Acanthosomatidae takes the name as a whole because….well, they’re shaped like a shield. They also have a spine on their abdomen adjacent to the rostrum. Again, most of these species suck plant juices.
– To 0.35″. Yellowish or yellow-green with red-brown patches. Dark bands on edge of abdomen. Found on birch and other plants. (photo © Edge-striped Shield Bug ( ) Elasmucha lateralis Harsi Parker)
Red Cross Shield Bug (– To 0.4″. Green to green-yellow with reddish X-mark on back. Spined shoulders. Found on many plants and trees, especially alder. (photo © Elasmostethus cruciatus) Harsi Parker)
Shield-backed Bugs (
This bug family is distinct in that their scutellum extends over their entire back, giving the appearance of a continuous shield and sometimes causing them to be mistaken for beetles. They are also known as “Jewel Bugs” due to the colorful appearance of some species. Like Stink Bugs they can produce a noxious smell. They feed on plant juices.
Ebony Bugs (
As with the shield-backed bugs, their scutellum extends over their entire back, causing them to be mistaken for beetles. They can be distinguished from beetles by their five-segment antennae and unique mouthparts. They feed on flowers and young seeds.
Black Bugs (– To 0.2″. Small, round, and shiny-black all over. There are several species in our area, including Corimelaena sp.) Corimelaena pulicaria and Corimelaena interrupta, that are difficult to tell apart. Found on weeds and short vegetation. (photo © mrp123)
Flat Bugs (
These unique bugs are as flat as their name suggests, adapted to live under the bark of dead trees. Most species are very drab in coloration. Little is known of their habits though it is assumed that they feed on fungus.
Dark-spotted Flat Bug (– To 0.25″. Mottled tan and black. Eyes project. Strong furrows on pronotum. Wings comparatively more prominent. Abdominal lobes are rounded, convex and flare. (photo © Aradus fuscomaculatus) Thomas Barbin)
– To 0.4″. Generally black, often brownish spot in middle. Scutellum triangular in this genus. Wings minimal. Sides parallel rather than rounded and convex. Longer antennae base than Reduced Flat Bug. (photo © Pacific Flat Bug ( ) Mezira pacifica James Bailey)
Bordered Plant Bugs (
These plant sap-feeding bugs get their name from the colorful borders on either side of their body. They are found both on the ground and crawling in shrubs and low plants.
Bordered Plant Bug (Largus cinctus) – To 0.7″. All of our local bordered plant bugs have the same dark oval body with orangish or reddish borders. Feeds on plants. (photo © Steven Soltesz)
Leaf-footed Bugs and relatives (
This superfamily of bugs gets its name from the broadly expanded rear legs in some species. Some emit an unpleasant odor when threatened, though “Scentless Plant Bugs” such at the Boxelder Bug do not have strong odor. They feed on the sap of plants, with some species specializing in young twigs while others focus on seeds.
Squash Bug (– To 0.65″. Oval in shape, gray to black with bands on abdominal margin. Pronotum is smooth and inconspicuous. Feeds on leaves of squash plants. (photo © Anasa tristis) littlequeen)
Western Conifer Seed Bug (– To 0.8″. Reddish-brown with faint light zig-zag on back. Pronotum is steep but smooth. Light/dark bands below the wings on the abdomen. Found in forest, feeding on the seeds of conifer cones. (photo © Leptoglossus occidentalis) Lee Cain)
Pacific Coast Leather Bug ( Coriomeris occidentalis ) – To 0.4″. Brown/orangish-brown with roughened appearance. Antennae are thickly “haired”. Steeply sloped pronotum is serrated and spined. Feeds on clover, alfalfa, and other plants. (photo © karenrichards)
Western Boxelder Bug (– To 0.55″. Dark body with red or reddish-orange veins. Often clusters in groups. Feeds on the growing seeds of trees like maple, boxelder, and ash. (photo © Boisea rubrolineata) Jesse Rorabough)
Hyaline Grass Bug (– To 0.3″. Variable in color, brown with yellowish, reddish, or greenish tint and can be light or dark. Feeds on the seeds of low weeds as well as hemp. (photo © Liorhyssus hyalinus) Steve Daniels)
Lupine Bug (– To 0.65″. Brown with light/dark banded on abdominal margin. Brown antennae are black/white at end. Long rear legs are serrated above the first joint. Found on wooded edges. Feeds on legumes. (photo © Megalotomus quinquespinosus) Gary Chang)
– To 0.6″. Dark brown to black, often resembling spider wasps. Dense hairs on head and pronotum. Found on wooded edges, feeding on bush clover and other legumes. (photo © Broad-headed Bugs ( ) Alydus sp. David Anderson)
Seed Bugs and relatives (
Of variable appearance though most tend towards drabber patterns of red, brown, gray, and white and have somewhat slender bodies. Their antennae only have four segments. As the name suggests, many bugs in this family are known to suck the nutritious interior out of young seeds, though some species drink plant sap or even attack other bugs. Many of the drab-colored species tend to be found on the ground and are known as “Dirt-colored Seed Bugs”.
Small Milkweed Bug (– To 0.5″. Dark gray to black with red cross across back and red line across pronotum. White spots towards rear. Found on milkweed, of which it eats the nectar and seeds. (photo © Lygaeus kalmii) Mark Leppin)
White-crossed Seed Bug (– To 0.4″. White cross in middle of body separates black sections above and below from red sections on sides. Found in fields and meadows, often on ragwort. (photo © Neacoryphus bicrucis) mrcarp)
Elm Seed Bug (– To 0.3″. Dark gray to black, has rusty tint to parts of the front half of body. Feeds on elm seeds though can be found on other trees. Introduced from Europe. (photo © Arocatus melanocephalus) John L. Richards)
Birch Catkin Bug (– 0.2″. Tannish to reddish, sometimes with silvery sections and a triangular scutellum distinct in color. head more prominent than Elm Seed Bug. Found on the flower spikes of birch trees. (photo © Kleidocerys resedae) corndog)
– 0.25″. A broad flat bug, rust-brown with black front of pronotum and black scutellum. Pacific Dirt-colored Seed Bug () Gastrodes pacificus G. intermedius is darker and less orange in color. Found on Douglas Fir where it sucks from cones. (photo © Harsi Parker)
Mediterranean Seed Bug (– 0.2-0.3″. Very sharply defined black shapes on a brown/bronze background. Often found in grass seed fields. Introduced from Europe. (photo © Xanthochilus saturnius) karenrichards)
Common Dirt-colored Seed Bug (– 0.2″. Black and brown, with distinct paired black/white spots in middle of abdomen. Found on ground and tree trunks, hunting for seeds. Introduced from Europe. (photo © Rhyparochromus vulgaris) David Anderson)
– 0.15″. Black body with black-tipped brown wings. Double row of spines on lower part of front leg. First two antennae segments are partly lightened. Found in dense vegetation, including nettle. (photo © Double-spined Seed Bug () Scolopostethus thomsoni Alex Bairstow)
– To 0.25″. Single row of spines below front leg. Distinct curved white spots on lower part of wings. Hunts seeds on the ground like other dirt-colored seed bugs. (photo © White-tipped Seed Bug () Scolopostethus diffidens Harsi Parker)
Tuxedo Bug (– To 0.25″. Black with six distinct white flecks (two at end often overlap to appear as one) and several tan and white diagonals. Found in cleared ground and weeded lots. Introduced from Europe. (photo © Raglius alboacuminatus) David Anderson)
False Chinch Bugs ( Nysius sp.) – 0.1-0.2″. These tiny, slender bugs are drab gray with transparent wings crossing over their bodies. Found on a wide range of plants including grains and vegetable crops. (photo © CA Clark)
Western Big-eyed Bug (– 0.15″. Drab brown/gray/black with large eyes. Broad head/body. Found in places with sparse clumps of vegetation, including fields, lots, and gardens. Feed on both plants and insects. (photo © Geocoris pallens) Eric Carlson)
– 0.3″-0.4″. A slender bug with very long slender legs. Similar to Spined Stilt Bug, but top of thorax bulges less and there is a short downcurved process on top of head. Feeds on fruit blossoms, stems, and insect eggs. (photo © Docked Stilt Bug ( Neoneides muticus) Noah Strycker)