Chemical-ecology
Guides
Milichiella bisignata
freeloader fly
Milichiella bisignata is a small dipteran in the family Milichiidae, commonly known as freeloader flies. The species was described by Melander in 1913 from North and Central America. Taxonomic status remains unsettled, with some sources treating it as a junior synonym of Milichiella lucidula while others maintain it as a valid species. Members of this genus are kleptoparasites, attracted to predatory insects and spiders actively consuming prey.
Milichiella lacteipennis
freeloader fly
Milichiella lacteipennis is a small, dark-colored fly in the family Milichiidae, commonly known as freeloader flies. The species has a cosmopolitan distribution, having been recorded from the Galápagos Islands, Japan, Madeira, Hawaii, and Argentina. It is a kleptoparasite that feeds on fluids from prey captured by predatory insects, particularly heteropteran bugs. The species was described by Loew in 1866.
Monarthrum
Monarthrum is a genus of bark beetles in the family Curculionidae, containing approximately five described species. These beetles are associated with dying and dead wood, particularly oak, and exhibit ambrosia beetle characteristics including attraction to host volatiles and potential fungal symbiosis. The genus has been studied for its chemical ecology, with specific compounds identified as attractants for monitoring purposes.
Monarthrum scutellare
ambrosia beetle
Monarthrum scutellare is a scolytine weevil (Coleoptera: Curculionidae: Scolytinae) native to North America. It is an ambrosia beetle, a guild that cultivates fungal symbionts within wood galleries rather than feeding directly on plant tissues. The species has been documented in British Columbia, Canada, where it has been detected using a combination of ethanol and synthetic 3-hydroxyoctan-2-one lures. Like other Monarthrum species, it poses potential threats as an invasive pest due to its cryptic lifestyle and association with forest ecosystems.
Mordellistena convicta
tumbling flower beetle, gall-boring beetle, inquiline beetle
Mordellistena convicta is a gall-boring beetle in the family Mordellidae, described by LeConte in 1862. The species is an inquiline that inhabits galls induced by the goldenrod gall fly (Eurosta solidaginis) on goldenrod plants (Solidago spp.). It has been studied as a model system for sequential radiation and host-associated speciation, with populations showing differentiation corresponding to the host races of their gall fly associates. Adults use olfactory cues from gall tissues to locate suitable host plants for mating and oviposition.
Myrmica
Furrowed Ants
Myrmica is a genus of ants in the subfamily Myrmicinae containing approximately 200 described species. The genus is widespread across temperate regions of the Holarctic and occurs in high mountain habitats of Southeast Asia. Myrmica species exhibit diverse colony structures, including both monogynous and polygynous forms. The genus is notable for its complex ecological relationships, including associations with parasitic butterflies, inquiline ant species, and various other organisms.
Odontomachus ruginodis
rough-node snapping ant, rough-node trap-jaw ant
Odontomachus ruginodis is a species of trap-jaw ant native to the southeastern United States, known for its powerful spring-loaded mandibles capable of snapping shut at high speeds. The species has been observed expanding its range northward from its previously known distribution centered on the Orlando, Florida area. Research has revealed that queens of this species use unique cuticular chemical compounds—specifically dialkyltetrahydrofurans—to distinguish themselves from workers, a signaling system distinct from both other Odontomachus species and the broader class of compounds once thought universal among eusocial insects. Like other trap-jaw ants, it is an active predator with a venomous sting.
Parasyrphus
Bristleside Flies
Parasyrphus is a genus of hoverflies (Syrphidae) comprising 31 described species distributed across the Holarctic region. Adults are small to medium-sized (5.6–11 mm) with characteristic yellow abdominal markings. The genus exhibits notable larval trophic diversity: most known larvae are aphid predators on trees, while at least two species (P. nigritarsis and P. melanderi) are specialist predators of leaf beetle eggs and larvae. This dietary specialization is unusual among syrphid flies and involves sophisticated chemical ecology where predators exploit prey defensive secretions as foraging cues.
Perillus bioculatus
two-spotted stink bug, double-eyed soldier bug
Perillus bioculatus is a predatory stink bug native to North America that has been introduced to Europe and Asia as a biological control agent. Both nymphs and adults are specialized predators of Colorado potato beetle (Leptinotarsa decemlineata) eggs and larvae, using toxic venom and digestive enzymes to subdue and liquefy prey. The species has established expanding populations in southeastern Europe, with recent records from Serbia, Hungary, Romania, and Turkey. Research demonstrates its ability to locate prey by detecting volatile compounds released by beetle-damaged potato plants.
Phloeosinus
cedar bark beetles, cypress bark beetles
Phloeosinus is a genus of bark beetles (Curculionidae: Scolytinae) comprising at least 20 described species. Species in this genus are specialized on conifers in the family Cupressaceae, including genera such as Cupressus, Thuja, Juniperus, and Chamaecyparis. Several species have become significant invasive pests, causing economic damage to ornamental trees and forest ecosystems. The genus exhibits specialized chemical ecology, with species using host plant volatiles and pheromones for mate and host location.
Phloeotribus
Phloeotribus is a genus of crenulate bark beetles in the family Curculionidae, comprising at least 150 described species. Species within this genus exhibit diverse host associations, with some specializing on olive (Olea europaea), others on stone fruits (Prunus spp.), and some on broom (Cytisus scoparius). The genus includes economically significant pests such as Phloeotribus scarabaeoides, which damages olive trees through feeding and breeding gallery construction. Reproductive systems vary among species, with both monogynous and bigynous mating systems documented.
Phloeotribus liminaris
Peach Bark Beetle
Phloeotribus liminaris, commonly known as the peach bark beetle, is a bark beetle species in the family Curculionidae. It has been documented colonizing black cherry trees (Prunus serotina) through chemically-mediated host location. The species is found in North America.
Photinus ignitus
Ignited Firefly
Photinus ignitus is a North American firefly species distinguished by its bioluminescent courtship displays. Males produce characteristic flash patterns to attract females, who respond from perches in vegetation. Research has documented seasonal plasticity in female mate choice behavior, with females becoming less selective as the breeding season progresses. Like other Photinus species, it produces defensive compounds called lucibufagins that protect against predators.
fireflybioluminescencemate-choiceseasonal-plasticitynuptial-giftaggressive-mimicryLampyridaeColeopteraNorth-Americaflash-communicationlucibufaginsexual-selectionoperational-sex-ratiocold-lightphotocytesluciferinluciferasenocturnalcourtshippredation-defenseinsect-declinelight-pollutionhabitat-lossinsecticide-exposuresoil-dwelling-larvaeglowwormpredatory-larvaesoft-bodied-preysnailsslugswormssoil-insectsbiological-controlflash-patternfemale-choicemale-choicebody-sizelantern-sizereproductive-investmentegg-provisioningspermatophoreflash-signalmating-successselectivitybreeding-seasondusknightvegetationgrasslawnsforestsfieldsedgescanopyairspaceColumbia-MarylandWashington-Baltimore-areaUniversity-of-Virginia-studylight-pollution-impactmating-disruptionurbanizationresidual-insecticideslawn-treatmentweather-cyclesfood-availabilitylarval-predationpopulation-fluctuationbanner-yearspectacleJuly-4thIndependence-DayMother-Nature's-fireworkspyrotechnictwinklinggalaxycold-light-efficiencyno-heat-productionphotocyte-cellsspecialized-light-organterminal-abdominal-segmentslightly-coloredgiant-eyesflash-detectionvisual-acuitynocturnal-visionchemical-ecologydefensive-chemistrysteroidal-pyronestoad-toxinsspider-repellentbird-repellentfemme-fatalepredatory-exploitationchemical-acquisitiondefense-sequestrationnuptial-feedingreproductive-successsexual-conflictflash-manipulationphotographic-challengeflash-rechargefemale-contortionflash-directionalityaimed-signalmale-expendabilityfemale-investmentoffspring-productionbattery-lifeconservation-concernpopulation-monitoringcitizen-scienceBoston-Museum-of-Sciencefirefly-data-projectAllegheny-National-Forestsynchronous-firefliesPhotinus-carolinusPhoturis-pennsylvanicaPennsylvania-Firefly-FestivalFIRE-TeamLynn-FaustSara-LewisThomas-EisnerAerial-FirebaughKyle-Hayneschemical-ecology-pioneerexperimental-studyfield-observationnatural-historybehavioral-ecologyethologyjournal-articlepeer-reviewed-researchscientific-investigationinsect-conservationnocturnal-insectbeetlesoft-winged-beetlenot-true-bugnot-flyElateroideaPolyphagaElateriformiaLampyrinaeLucidotiniaccepted-nameFall-192736-observationsiNaturalistGBIFCatalogue-of-LifeNCBIWikipediaBug-of-the-WeekEntomology-Todayincomplete-informationdata-limitedresearch-opportunityfurther-study-neededPhoturis
femme fatale lightning bugs, predatory fireflies
Photuris is a genus of predatory fireflies in the family Lampyridae, comprising at least 64 species restricted to temperate North America. Adult females are notable for aggressive mimicry: they imitate the bioluminescent flash signals of females from other firefly genera—primarily Photinus and Pyractomena—to attract, capture, and consume unsuspecting males. This predatory behavior allows Photuris females to obtain high-quality protein meals and acquire defensive chemicals called lucibufagins from their prey. The genus has been extensively studied for its remarkable coevolution of signal systems and chemical ecology.
Photuris congener
Florida Single Snappy
Photuris congener is a firefly species in the predatory genus Photuris, first described by LeConte in 1852. Like other Photuris species, females are known to practice aggressive mimicry, luring males of other firefly genera through flash pattern imitation. The species is commonly known as the 'Florida Single Snappy' and occurs in North America. As with congeners, it produces bioluminescence through a luciferin-luciferase reaction in specialized abdominal photocytes.
Photuris fairchildi
Cape Breton Firefly
Photuris fairchildi is a predatory firefly species in the beetle family Lampyridae, described by Barber in 1951. It is known from Nova Scotia, Canada, where it inhabits marshes, spruce forests, and low-lying swampy areas. The species exhibits aggressive mimicry, using bioluminescent flash signals to lure and prey upon males of other firefly species. Courtship involves distinct flash communication patterns between males and females.
Phyllotreta armoraciae
Horseradish Flea Beetle
Phyllotreta armoraciae is a monophagous flea beetle specialized on horseradish (Armoracia rusticana). Research has identified its unique feeding chemistry: the beetle requires synergistic combinations of glucosinolates and flavonol glycosides (specifically kaempferol 3-O-xylosylgalactoside and quercetin 3-O-xylosylgalactoside) for feeding stimulation, marking the first documented case of a crucifer-feeding insect using non-glucosinolate allelochemicals as feeding stimulants. Two subspecies are recognized: P. a. armoraciae and P. a. biplagiata.
Pityogenes bidentatus
Pityogenes bidentatus is a European bark beetle that colonizes Scots pine (Pinus sylvestris). The species exhibits sophisticated olfactory-mediated behaviors for host location, including attraction to aggregation pheromone components (grandisol and cis-verbenol) and active avoidance of nonhost volatiles. Its behavioral response to monoterpene odors is context-dependent: avoidance occurs during flight but not during walking, likely representing distinct sensory mechanisms for long-range host discrimination versus short-range gallery establishment.
bark-beetleScolytinaePinus-sylvestrisaggregation-pheromoneolfactory-behaviorhost-selectionmonoterpene-avoidancecontext-dependent-plasticitynonhost-avoidancenorthern-Europegrandisolcis-verbenol1-octene-3-olβ-caryophylleneflight-behaviorwalking-behaviorelectroantennographypopulation-genetics-modelnematode-associationBursaphelenchus-pinophilusnematangiaCzech-Republicmixed-forestconifer-forestScots-pineNorway-sprucenonhost-volatileschemical-ecologyinsect-plant-interactionsherbivore-host-rangesensory-ecologybehavioral-plasticitypheromone-ecologyforest-entomologyinvasive-potential-(North-America-records)Pityophthorus
Pityophthorus is a large genus of bark beetles in the family Curculionidae, containing more than 540 described species. The genus is characterized by its association with coniferous and hardwood host trees, with species distributed across North America, Europe, and other regions. Some species, such as P. juglandis (the walnut twig beetle), are significant forest pests that vector pathogenic fungi causing tree diseases.
Pityophthorus juglandis
Walnut Twig Beetle
Pityophthorus juglandis is an invasive bark beetle native to the southwestern United States and Mexico that vectors the fungal pathogen Geosmithia morbida, causing thousand cankers disease in walnut trees. The beetle measures approximately 1.5 mm in length and is among the few Pityophthorus species associated with hardwoods. Research has focused extensively on its chemical ecology, including the male-produced aggregation pheromone 3-methyl-2-buten-1-ol and potential semiochemical repellents for management. The species exhibits strong host discrimination during flight, preferentially landing on Juglans species while avoiding most non-host hardwoods.
Polyergus breviceps
Broad-headed Amazon Ant
Polyergus breviceps is an obligate slave-making ant endemic to the United States. Workers are incapable of foraging, feeding brood, or performing nest maintenance, relying entirely on enslaved Formica workers for all colony tasks. The species conducts organized raids on Formica colonies to capture pupae, which mature into workers in the mixed nest. Newly mated queens can independently usurp Formica colonies through a combination of physical combat and chemical deception.
Polyphylla sobrina
Polyphylla sobrina is a species of scarab beetle in the family Scarabaeidae, commonly known as the ten-lined June beetle. It is native to western North America, with documented occurrences in California, Nevada, and Utah. The species belongs to a genus characterized by males with enlarged, fan-like antennae used to detect female sex pheromones. Research on this species has been notably challenging due to the extremely small quantities of its pheromone, which has resisted isolation and structural identification for decades.
Protopiophila litigata
Antler Fly
Protopiophila litigata, commonly called the antler fly, is a small piophilid fly endemic to North America. The species is distinguished by its exclusive reliance on discarded cervid antlers as a breeding substrate—a highly unusual and ephemeral resource that has driven the evolution of extreme territorial behavior and lifelong site fidelity in males. Males defend territories on antlers with remarkable aggression, engaging in frequent combat with rivals and even attacking much larger insects. This unique ecology has made P. litigata a model organism for studying senescence, sexual selection, and life history trade-offs in wild insect populations.
Pseudosphinx tetrio
tetrio sphinx, giant gray sphinx, frangipani hornworm, plumeria caterpillar, Rasta caterpillar
Pseudosphinx tetrio is a sphinx moth (Sphingidae) native to tropical and subtropical regions of the Americas. Its larvae are specialized herbivores of Apocynaceae plants, particularly Allamanda cathartica and Plumeria species. The species exhibits a distinctive chemical ecology strategy: larvae selectively excrete plant-derived compounds rather than sequestering or metabolizing them, enabling them to feed on toxic host plants rich in latex. The caterpillars display aposematic coloration—velvety black with yellow rings and orange-red head and legs—advertising their unpalatability to predators.
Psila rosae
carrot fly, carrot rust fly
Psila rosae, commonly known as the carrot fly or carrot rust fly, is a dipteran pest of cultivated umbelliferous crops. Adults orient to host plants using volatile chemical cues from carrot foliage, with strong electroantennogram responses to propenylbenzenes such as trans-asarone and trans-methylisoeugenol. Larvae feed on carrot roots, causing characteristic mining damage that reduces crop quality and yield. The species has a broad geographic distribution spanning Europe, Asia, North America, and New Zealand. Overwintering occurs as both larvae and pupae, with temperature-dependent diapause in pupae contributing to population synchronization and the potential for multiple generations per year.
Scaptomyza flava
European leaf miner, yellow scaptomyza
Scaptomyza flava is an obligate herbivorous leaf-mining fly in the family Drosophilidae, representing an evolutionary transition to herbivory from the ancestral microbe-feeding habit of drosophilids. Adults are 2.5 mm in length and amber to dark brown in color. The species is native to the Palearctic region with a Holarctic distribution across Europe, Asia, and North America, and has been introduced to New Zealand and Australia where it is a significant agricultural pest of Brassicales crops. Larvae feed internally on leaf mesophyll, creating serpentine mines that mature into blotches. The species is unusual among Drosophilidae in having lost yeast-associated odorant receptors and evolved specialized detoxification mechanisms for mustard oils. It is being developed as a model organism for studying plant-herbivore interactions.
Scolopostethus pacificus
Scolopostethus pacificus is a myrmecophilous dirt-colored seed bug that lives in close proximity to nests of the velvety tree ant (Liometopum occidentale). Unlike many ant-associated parasites that rely on chemical deception through cuticular hydrocarbon mimicry, this species employs chemical weaponry—releasing volatile compounds from its metathoracic glands to moderate encounters with its aggressive host. Molecular gut barcoding has confirmed that S. pacificus does not feed on its host ant, distinguishing its relationship as commensal or inquiline rather than parasitic. The species is native to western North America.
Sinella curviseta
Sinella curviseta is a slender springtail in the family Entomobryidae, widely used as a model organism in soil ecology and ecotoxicology. The species produces curvisetone, a male-specific tricyclic nor-diterpenoid with an unprecedented carbon skeleton, which peaks before oviposition and may function in reproductive communication. It is among the most abundant soil arthropods in many temperate ecosystems.
Sirex nigricornis
black-horned woodwasp, native woodwasp
Sirex nigricornis is a native North American woodwasp (family Siricidae) that inhabits pine forests in the eastern United States. Unlike the invasive congener Sirex noctilio, this species primarily attacks stressed, dying, or recently dead pines rather than healthy trees. Females possess a prominent ovipositor for drilling into wood and deposit eggs along with a symbiotic wood-decaying fungus. The species serves as host for multiple parasitoids including the nematode Deladenus proximus, which sterilizes female eggs, and the ichneumonid wasp Rhyssa howdenorum.
Sphenophorus parvulus
bluegrass billbug
Sphenophorus parvulus, commonly known as the bluegrass billbug, is a small weevil native to North America and a significant pest of turfgrass, particularly Kentucky bluegrass. Adults measure approximately 5–7 mm in length, with a distinctive long, downward-curving rostrum comprising about one-third of the body length. The species was described by Swedish entomologist Leonard Gyllenhaal in 1838, with the specific epithet derived from Latin 'parvus' meaning small. It is one of at least ten Sphenophorus species that damage turfgrass in the United States and is frequently studied in the context of integrated pest management and host plant resistance.
Sphenophorus venatus venatus
hunting billbug
Sphenophorus venatus venatus is a subspecies of hunting billbug, a weevil in the family Dryophthoridae. It is widely distributed across North America and has been documented in Middle America, Spain, and Corsica. This subspecies is associated with grass habitats, particularly Cynodon dactylon (bermudagrass), and exhibits chemically-mediated host and mate recognition behaviors. Males are attracted to host-plant volatiles and conspecific cues, while females respond to male conspecifics. The species uses both volatile and contact chemical cues for orientation and recognition.
Stenolemus
Spider Assassin Bugs
Stenolemus is a genus of thread-legged assassin bugs (Emesinae) characterized by specialized araneophagy—predation on spiders. Species in this genus exhibit diverse hunting strategies, including web invasion and exploitation of spider draglines as prey location cues. The genus has a broad geographic distribution spanning Australia, Asia, and the Pacific region. Multiple species have been described, with S. bituberus and S. giraffa being the most extensively studied for their predatory behavior and life history.
Temnoscheila
bark-gnawing beetles
Temnoscheila is a genus of predatory bark-gnawing beetles in the family Trogossitidae, containing approximately 19 described species. Members of this genus are agile beetles often found in association with bark and wood of trees. At least one species, T. virescens, has been demonstrated to use cerambycid beetle pheromones to locate its prey, indicating sophisticated chemical eavesdropping behavior. The genus was historically often misspelled as "Temnochila" in literature.
Temnoscheila virescens
Temnoscheila virescens is a predatory beetle in the family Trogossitidae, commonly known as bark-gnawing beetles. Research demonstrates that this species is attracted to cerambycid beetle pheromones, specifically 3-hydroxyhexan-2-one, with ethanol enhancing this attraction. This chemical eavesdropping behavior indicates a predator-prey relationship with longhorn beetles (Cerambycidae). The species belongs to a family whose members are typically associated with dead or dying wood habitats.
Temnothorax ambiguus
Doubtful Acorn Ant
Temnothorax ambiguus is an ant species in the subfamily Myrmicinae, commonly known as the Doubtful Acorn Ant. It serves as a host species for the obligatory slave-making ant Protomognathus americanus and exhibits facultative slave-making behavior itself. Laboratory studies demonstrate sophisticated larval recognition capabilities, with workers preferentially accepting nestmate larvae and discriminating between conspecific and allospecific brood. The species has been observed in contexts involving cavity-nesting habits typical of the genus, including nesting in hollow nuts and acorns.
Tetanolita mynesalis
Smoky Tetanolita, Smoky Tetanolita Moth
Tetanolita mynesalis, known as the smoky tetanolita, is a small litter moth in the family Erebidae. First described by Francis Walker in 1859, it occurs in eastern North America with adults active from late spring through late autumn. The species is notable as a prey item of bolas spiders, which chemically mimic its female sex pheromones to attract males.
Tetropium cinnamopterum
Eastern Larch Borer
Tetropium cinnamopterum is a native North American cerambycid beetle in the tribe Tetropiini. Adults are distinguished from the closely related T. parvulum by eye shape, scutellar structure, external genitalia, and pronotal puncture number; larvae are distinguished by urogomphi morphology. The species has been recorded from various conifer hosts, with larvae developing in conifer wood. It is transcontinental in Canada and occurs sympatrically with invasive T. fuscum in Atlantic Canada, where cross-attraction to the aggregation pheromone fuscumol may occur. Both sexes respond to (S)-fuscumol synergized by host monoterpenes and ethanol.
Thanasimus dubius
dubious checkered beetle, American bark beetle destroyer, checkered beetle predator, Wavering Checkered Beetle
Thanasimus dubius is a predatory checkered beetle (Cleridae) native to North and Central America. It specializes in preying upon bark beetles, particularly species in the genera Ips and Dendroctonus, with the southern pine beetle (Dendroctonus frontalis) being a well-documented prey item. Adults exhibit a stereotyped five-act predatory sequence involving search/ambush, seizure, alignment, consumption, and grooming. The species demonstrates chemotactic responses to bark beetle pheromones and tree volatiles, and shows regional genetic differentiation across its eastern North American range. It has been investigated as a potential biological control agent for forest pest management.
Thaumatomyia glabra
grass fly
Thaumatomyia glabra is a species of grass fly in the family Chloropidae, first described by Meigen in 1830. The species has been documented in Europe (Denmark, Norway, Sweden) and North America (Vermont, Hawaii). A notable behavioral trait is its attraction to methyl anthranilate, a compound found in plants such as Iris pallida.
Trachymyrmex septentrionalis
Northern Fungus-farming Ant
Trachymyrmex septentrionalis is a fungus-farming ant in the tribe Attini, notable as the northernmost attine species. It cultivates symbiotic fungal gardens in underground nests, primarily in sandy soils. The species exhibits sophisticated garden hygiene behaviors, detecting and removing pathogen-infected garden material using chemical cues. Population dynamics are strongly influenced by drought conditions, with colonies concentrating in mesic microhabitats during dry periods.
Trichobaris
flower weevils
Trichobaris is a genus of flower weevils in the family Curculionidae, comprising 8–13 described species distributed from the southwestern United States through Mexico. These weevils are specialized herbivores associated with plants in the family Solanaceae, particularly the genus Datura, with which they likely coevolved. Several species are notable agricultural pests, including T. mucorea (tobacco stalk borer) and T. trinotata (potato stalk borer), which also feed on cultivated solanaceous crops. Research on this genus has contributed to understanding host-herbivore coevolution, chemical ecology of host selection, and the decoupling of maternal oviposition cues from larval performance.
Trichobaris mucorea
tobacco stalk borer
Trichobaris mucorea is a flower weevil in the family Curculionidae, commonly known as the tobacco stalk borer. The species is specialized on host plants in the genus Nicotiana, particularly Nicotiana attenuata, where it completes most of its life cycle concealed within stems. Adult females use volatile chemical cues to select oviposition sites, though these cues do not necessarily predict larval performance. The species is native to North America.
Trogus pennator
Trogus pennator is a parasitoid wasp in the family Ichneumonidae that attacks larvae of swallowtail butterflies (Papilionidae), particularly in the genera Eurytides and Papilio. Females locate hosts using chemical cues from larval frass and feeding damage. The species is deterred from parasitizing Battus philenor due to aristolochic acid sequestration by that host. It has been recorded in North America including Vermont.
Tupiocoris notatus
Suckfly
Tupiocoris notatus is a small mirid bug (2–3 mm) specializing on Solanaceae host plants. It feeds on mesophyll cell contents of plants such as Datura wrightii and Nicotiana attenuata. The species undergoes incomplete metamorphosis with multiple nymph stages. It has become an important model organism for studying plant-herbivore chemical ecology and host plant-specific transcriptional responses.
Xystocheir
Xystocheir is a genus of flat-backed millipedes in the family Xystodesmidae, endemic to California. The genus comprises nine species distributed in the Coast Ranges and Sierra Nevada. Members of this genus are notable for producing cyanide as a chemical defense against predators. Xystocheir dissecta, a species within this genus, has been documented to fluoresce under ultraviolet light.