Key to Families of Coleoptera in British Columbia

I. Key to subfamilies of Coleoptera in British Columbia


Notopleural sutures present, OR abdomen with only 3 visible sterna, soft-bodied beetles, less than 2.6 mm long, and with wings rolled in a spiral "cigar" manner (not folded)



Notopleural sutures absent; abdomen with 4 or more visible sterna; wings folded or not, but not rolled



2 (1).

Hind coxae immovably fused to metasternum, completely dividing first visible abdominal sternum



Hind coxae freely moveable, first visible abdominal sternum extending entirely across abdominal venter behind them



II. Key to families of Archostemata


Notopleural sutures present; elytra reticulate, long, covering pygidium; body covered with scales; antennae filiform to subserrate; length over 4 mm




Notopleural sutures absent; elytra smooth, short, and leaving at least pygidium exposed; body without scales; antennae sub-moniliform and gradually widened from fourth segment; length less than 2.6 mm



III. Key to families of Adephaga


Hind coxae greatly enlarged, with ventral plate concealing trochanter and basal half of femur, and covering most of first three basal abdominal sterna



Hind coxae not greatly enlarged, or if so, then all abdominal sterna visible, coxae not concealing trochanter, basal half of femur and first three abdominal sterna



2 (1).

Hind coxa not reaching elytron laterally; metepimeron and first abdominal sternum in contact laterally of hind coxa, and mesad of elytral margin; antennae usually at least partly pubescent, in addition to scattered long sensory setae; fore coxal cavities usually closed behind; IF hind coxa reach elytron and fore coxal cavities open, THEN first visible abdominal sternum 3X as long as hind coxa, at insertion of leg AND last segment of maxillary palp distinctly narrower than penultimate



Hind coxa reaching elytron laterally, junction of metepimeron and first abdominal sternum not visible, when elytron in place; antennae not pubescent, but with only scattered long sensory setae; fore coxal cavities open behind; first visible abdominal sternum 3X as long as hind coxa; last segment of maxillary palp not distinctly narrower than penultimate



3 (2).

Mentum expanded, fused laterally to head capsule, covering ventral mouthparts completely when mandibles closed; mentum extending anteriorly beyond other mouthparts to form cutting edge; outer angle of fore tibia with large inwardly curved uncus; body cylindrical; antennal moniliform; head, pronotum, and elytra with deep canaliculate grooves




Mentum not fused laterally to head capsule, and not extending beyond other mouthparts, maxilla and labium with at least palps visible; outer angle of fore tibia with straight or outwardly curved teeth or spines; head, pronotum and elytra without deep canaliculate grooves; body form and antennae variable



4 (2).

Fore tibia with antennal cleaner on inner apical angle; head with supraorbital setae



Fore tibia without antennal cleaner on inner apical angle; head without supraorbital setae



5 (4).

Second antennal segment (pedicel) greatly enlarged, offset from main line of antenna; rest of antennae terminally (flagellum) very short and compact, not extending beyond hind margin of head; middle and hind legs very short; eyes usually divided into two isolated parts on each side (rarely with only a very narrow canthus extending between upper and lower portions)



Second antennal segment (pedicel) normal, antenna extending beyond hind margin of head; middle and hind legs not especially short; eyes not divided



6 (5).

Hind femur and hind tibia narrow and subcylindrical in cross section; hind tarsus shorter than hind tibia, and not tapering distally; body not streamlined, outline of pronotum and elytron being discontinuous; base of pronotum distinctly narrower than elytra; length 11-16 mm



Hind femur and hind tibia more or less distinctly flattened; hind tarsus usually as long as or longer than hind tibia, and distinctly tapering distally; body streamlined, outline of pronotum and elytra usually continuous; length 1-40 mm



IV. Key to families of Polyphaga


Elytra present, complete, short or reduced to flap-like stubs on mesothorax



Elytra totally absent; females



2 (1).

Antenna strongly asymmetrical, usually lamellate club of 3-8 segments; fore coxae large, strongly transverse or conical and projecting below prosternum; fore coxal cavities closed; trochantins concealed; fore tibia flattened with one or more teeth on outer edge; tarsi with 5 distinct segments, none of which are lobed or densely pubescent



Antennae not lamellate, or coxae, tibiae or tarsi not as above



3 (2).

Antennae 11-segmented



Antennae with fewer than 11 segments



4 (3).

Middle tibia with long apical spur pectinate along one edge



Middle tibia with longer apical spur simple, not pectinate



5 (4).

Segments of antennal club not capable of being tightly closed together



Segments of antennal club capable of being tightly closed



6 (5).

Abdomen with 5 visible sterna; dorsal surface roughened and tuberculate, not shining



Abdomen with 6 visible sterna; dorsal surface variably sculptured, shining or not



7 (6).

Eyes divided by prominent canthus; clypeus with sides subparallel to divergent anteriorly; colour testaceous to light reddish-brown; hind femora and hind tibiae enlarged, covering most of abdomen



Eyes not divided by canthus; clypeus with sides narrowing apically; colour brown, gray, or black; hind femora and hind tibiae not enlarged, not covering abdomen



8 (6).

Elytra shortened and widely divergent at apex, not covering pygidium; eighth morphological abdominal segment with spiracle



Elytra not shortened or widely divergent at apex, pygidium exposed or not; eighth morphological segment lacking spiracle



9 (2).

Tarsi pseudotetramerous on all legs, with apparent penultimate segment lobed below, enclosing or nearly hiding true fourth segment; often with long antennae, rostrate head or enlarged hind femora; hind coxa without exposed posterior face



Tarsi with 2-5 segments not pseudotetramerous on ALL legs (i.e. third of 5 segments on hind leg not lobed and enclosing small fourth, but any other configuration possible); antennae, mouthparts, femora and hind coxae variable; OR tarsi pseudotetramerous and hind coxae with distinct posterior face (at least medially) set off from ventral surface by a carina or flange; OR tarsi pseudotetramerous, head not at all rostrate, and antennae strongly or weakly clubbed, but not geniculate



10 (9).

Palps on mouthparts very short, usually immovably fixed and not visible;; head rostrate, prolonged into a variously developed beak AND/OR antennae geniculate with compact club



Palps on mouthparts longer, flexible, and usually evident; head usually not prolonged into a beak, but if rostrate or antennae elbowed and club compact, then palps longer and flexible



11 (9).

Antennae distinctly clubbed, with 4 or fewer segments in club; OR if antennal moniliform, head distinctly rostrate; OR if club with 5 or more segments, length of head from vertex to clypeal margin greater than width of head just behind eyes



Antennae usually without distinct club, filiform, moniliform, serrate or pectinate; head not rostrate; if antennae distinctly clubbed, then club of 5 or more segments and length of head to clypeal margin less than or equal to width of head just behind eyes



12 (11).

Antennae usually more than half length of body, often inserted on prominence, and capable of being reflexed backward over body; tibiae with 2 obvious apical spurs; first antennal segment usually several times longer than second; pygidium never sclerotized and exposed; length 3 to 75 mm



Antennae usually less than half length of body, seldom inserted on prominence, and not flexible back over body; tibiae without or with one or 2 apical spurs; first antennal segment seldom more than 2 to 3 times length of second; pygidium of some species sclerotized and exposed; length usually less than 12 mm



13 (12).

All tibiae with 2 distinct apical spurs, AND frons without "X" grooves; mesonotum with or without stridulatory file; ligula large, membranous and bilobed



At least one tibia without 2 apical spurs OR frons with deep "X" grooves; mesonotum without stridulatory file; ligula normal



14 (13).

Elytra usually with more or less evident epipleura, seldom strongly abbreviated exposing pygidium, if latter exposed seldom declivous; if body oval, venter not strongly convex



Elytra without epipleura, abbreviated posteriorly, exposing a declivous pygidium; body oval, with ventral strongly convex



15 (13).

Head with short, but distinct temple behind eye, set off from narrowed neck; apex of mandible bidentate; ligula with a single lobe; mesonotum with stridulatory file



Head lacking temples, evenly narrowed from behind eyes to neck; apex of mandible unidentate or bidentate; ligula bilobed; mesonotum without stridulatory file



16 (11).

Antennae geniculate (rarely appearing straight or nearly so), club compact; hind trochanter not cylindrical, femur attached obliquely



Antennae straight (very rarely geniculate), club loose or not evident; hind trochanter variable, but if antennal geniculate, trochanter cylindrical and squarely attached to femur



17 (16).

Labrum visible and free; second tarsal segment not spongy beneath; maxillary palps normal



Labrum never free; tarsi variable; maxillary palps rigid



18 (17).

Antennae situated adjacent to eye or laterally near base of short dorsoventrally flat rostrum; apex of third antennal segment reaching well beyond front margin of eye; all tibiae lacking spurs or spurs vestigial; notosternal sutures indistinct to obsolete



Antennae situated distally on long cylindrical rostrum; apex of third antennal segment not or barely reaching front margin of eye; all tibiae with spurs; notosternal sutures distinct



19 (17).

Antennae straight and clubbed; body pear-shaped, and hind trochanter cylindrical, squarely joined to femur



Antennae straight, not elbowed, but with 11 segments and a distinct club; hind trochanter triangular or diamond-shaped, obliquely joining to femur; body form variable



20 (10).

Body length 1.2 mm or less; antennae long, thin, with loose to indistinct club; antennal segments each with a whorl of long setae at apex; hind wings fringed with long setae that are longer than width of wing, or hind wings absent



Body length variable; antennae not as above; hind wings rarely with fringe longer than width of wing



21 (20).

Head with paired ocelli



Head without paired ocelli, at most with a single ocellus



22 (21).

Anterior edge of scutellum abruptly and sharply elevated above mesoscutum; metepisternum reaching middle coxal cavity and contacting first abdominal sternum to separate hind coxa from elytral edge



Anterior edge of scutellum not abruptly elevated, continuous with mesoscutum; metepisternum variable



23 (22).

Elytra completely covering abdomen; antennae short, not reaching middle of pronotum; antennae 9-segmented, with club of 5 pubescent segments; underside of body with hydrofuge pubescence

(Subfamily Ochthebiinae)


Elytra usually exposing one or more abdominal terga; antennae short to long, reaching beyond middle of pronotum in species with long elytra; antennal club, if present, not involving 5 segments; underside of body without hydrofuge pubescence

(Subfamily Omaliinae)


24 (20).

Elytra very short, leaving 3 or more abdominal terga exposed



Elytra longer, leaving no more than one or 2 abdominal terga exposed



25 (24).

Hind tarsus with one fewer segments than middle tarsus



Hind and middle tarsus with same number of segments



26 (25).

Antenna strongly serrate to pectinate, flabellate, bipectinate or biflabellate



Antennae at most, very weakly serrate



27 (26).

Tarsal claws with long, acute process or blade arising from base, usually more than half as long as claw; antennae filiform; body corpulent and soft

MELOIDAE (in part)


Tarsal claws simple; antennae weakly clubbed; body cylindrical

(Subfamily Euaesthetinae)


28 (25).

Scutellary striole present; basal two abdominal sterna united, suture not diminished medially antennae of males pectinate to flabellate or plumose



Scutellary striole absent; all abdominal sterna free, or 4 sterna united; antennae variable



29 (28).

Antennae with distinct club



Antennae without club



30 (29).

Middle tarsus with 2, 3 or 4 segments



Middle tarsus with 5 segments



31 (30).

Antennae with 4 apical segments expanded into asymmetrical club, first segment shining, other 3 tomentose; elytra usually some combination of black and orange, but occasionally all black; fifth abdominal tergum with a pair of longitudinal carinae topped by stridulatory files; body length 12 mm or more

SILPHIDAE (in part)

Individuals of Thanatophilus (Silphidae) with extended abdomen should key out here, because of antennal characters, but beetles in this genus lack the stridulatory files on the fifth abdominal tergum, and are only 8 to 14 mm long.


Antennae not as above; fifth abdominal tergum without stridulatory files; colour variable; body length 13 mm or less, usually less than 10 mm long



32 (31).

Antennae with 3 segments only; pronotum with antennal pockets antero-laterally above lateral margins; dorso-ventrally flattened, and louse-like; parasites of beavers

(Genus Platypsyllus)


Antennae 9 to 11-segmented; pronotum without antennal pockets



33 (32).

Fore coxal cavities open



Fore coxal cavities closed



34 (29).

Middle tarsus with 4 or fewer segments



Middle tarsus with 5 segments



35 (34).

Head covered above by pronotum; often with luminous organs on abdomen

LAMPYRIDAE (in part)


Head visible from above; never with luminous organs



36 (35).

Pronotum with lateral eversible vesicles

(Subfamily Malachiinae)


Pronto without eversible vesicles



37 (36).

Elytra individually rounded, not meeting apically at suture; mandibles long and narrow



Elytra truncate, meeting at suture apically; mandibles often short and broad



38 (24).

Apices of penultimate 2 or 3 antennal segments each completely ringed with microsetose groove (periarticular gutters) [must be viewed distally, difficult to see in very small specimens or in those with very compact antennal club]; antennae with distinct to indistinct loose club; prothorax with sharp lateral margins; abdomen with 5 or 6 visible sterna; fore trochantin exposed or hidden, if hidden and antennae 11-segmented, segment 8 smaller than segment 7 or 9



Antennae usually lacking periarticular gutters on antennal club; other characters variable; if complete periarticular gutters present, fore trochantin hidden, antennae 11-segmented AND segment 8 not smaller than segment 7 or 9



39 (38).

Hind tibial spurs subequal in length; body small (1 to 6 mm), round to elongate oval, shining, granulate or transversely strigulate; elytra glabrous or pubescent, striate or not; prothorax as broad as elytra; fore coxae strongly projecting and constricted by fore coxal cavity; often capable of retracting into a ball-shape by curling head and prothorax under body; antennae distinctly clubbed, often with 11 segments, 5 of which are involved in club, and segment 8 smaller than 7 or 9 (some genera with 10 or 11-segmented antennae and with distinct club of 3 or 4 segments, have flattened, externally flanged hind femora, apical portion of which are excavate to receive tibiae); tarsal formula highly variable 3-3-3, 4-4-4, 5-4-4, or 5-5-5; the genus Colon with 11-segmented antennae and somewhat gradually clubbed antenna lacking small segment 8, has elytra pubescent

LEIODIDAE (in part)


Hind tibial spurs distinctly unequal; body moderately sized (4 to 14 mm), somewhat flattened and shining; elytra striate or glabrous; pronotum somewhat narrowed relative to elytra; fore coxae strongly projecting and transverse; body not retractile; antennae long, club loose and indistinct, with segment 8 never smaller than 7 and 9; femora simple; tarsal formula 5-5-5

AGYRTIDAE (in part)


40 (38).

Middle tarsus with 3 apparent segments, either clearly with 3 segments, or second segment strongly lobed and hiding small penultimate (third) segment



Middle tarsus with 4 or 5 distinct segments OR first segment distinctly lobed, engulfing very small second and small third of fourth, appearing to have 2 or 3 segments



41 (40).

Middle tarsus pseudotrimerous, with second segment strongly lobed, hiding small penultimate (third) segment



Middle tarsus truly with 3 segments, second segment not greatly lobed



42 (41).

Fore coxal cavities closed; head small, usually covered by hood-like pronotum; if head exposed from above, then fore coxal cavities closed ;very small beetles, less than 2 mm long



Head visible from above in front of pronotum; fore coxal cavities open; size up to 11 mm long



43 (42).

Frontoclypeal suture distinctly impressed; all abdominal sterna free; pronotum often with sublateral lines



Frontoclypeal suture absent; 2 basal abdominal sterna united, first with postcoxal lines; pronotum lacking sublateral lines



44 (40).

Antennae 9-segmented, last 5 involved in club; abdomen with 6 or 7 visible sterna; with minute intercoxal sclerite between hind coxae; maxillary palp long relative to antenna; body ventrally with hydrofuge pubescence



Antennae not as above; other characters not in above combination



45 (44).

Antennae 7-9 segmented, segments 7-9 usually forming loose, tomentose club, segment 6 often forming a cupule at base of club; maxillary palp often as long as or longer than antenna, always more than half antennal length; hind coxae with ventro-posterior carina setting off convex posterior face, that rotates against anterior excavation of first visible abdominal sternum; planes of ventral surface of hind coxa and first abdominal sternum discontinuous; hind trochanter inserted on ventral (not posterior) surface of hind coxa, femur being held against ventral face of coxa, but not against posterior face of coxa or flat onto abdominal surface when fully retracted



Antennae variable, but not as above; maxillary palp usually much shorter than antenna; hind coxa configured differently



46 (45).

Hind coxa with distinct posterior face (at least medially), set off from ventral surface by carina or flange, with posterior face often excavated; ventral surface of hind coxa not co-planar with first visible abdominal sternum; hind femur inserted on posterior face of hind coxa and femur held posterior to coxa when retracted; fore coxal cavities open; middle and hind tarsi with equal number of segments



Hind coxa without distinct posterior face; hind trochanter often inserted on ventral surface or on small medial projection of coxa, never received in coxa; excavation and resting ventral to hind coxa in retracted position; ventral surface of hind coxa more or less continuous with first visible abdominal sternum OR hind tarsus with one fewer segment than middle tarsus; fore coxal cavities open or closed



47 (46).

Abdomen with 7 or 8 visible abdominal sterna; hind tarsus with 5 segments



Abdomen with 6 or fewer visible abdominal sterna; hind tarsus with 4 or 5 segments



48 (47).

Middle coxae distinctly separated; elytra often reticulate, at least feebly costate; femur and/or tibia compressed; pronotum with distinct median longitudinal carina, groove or cell, occasionally restricted to base of disc



Middle coxae contiguous or nearly so; elytra not reticulate; femur and tibia seldom compressed; pronotum rarely with distinct median longitudinal carina, groove or cell



49 (48).

Pronotum extended forward, covering head in dorsal view; abdominal venter with one or more sterna often with luminous organs (most obvious in males); separation of antennae insertions equal to or less than diameter of antennal fossa

LAMPYRIDAE (in part)


Head exposed in dorsal view when extended, OR if covered by pronotum, antennae separated by nearly twice diameter of antennal fossa; abdominal venter lacking luminous organs



50 (47).

Posterior angles of prothorax acute, embracing elytral humeri; hind tarsus with 5 segments; abdominal venter with 3 or more sterna united; prothorax dorsoventrally mobile relative to mesothorax; intercoxal process of prosternum long, notched dorsally, and received in deep middle coxal cavity as a clicking mechanism; IF clicking mechanism not visible owing to portion of intercoxal process being flat ventrally and received tightly in deeply emarginate mesosternum, THEN sternopleural suture or hypomeron grooved to receive antennae



Posterior angles of prothorax not acute and embracing elytral humeri, or rarely somewhat acute and weakly embracing humeri; hind tarsus with 4 or 5 segments; abdominal sterna variable; prosternal process variable, but if large and received in deeply emarginate mesosternum, apex of prosternal process not notched dorsally, nor capable of clicking; if large prosternal process received tightly in deep middle coxal cavity AND underside of prothorax grooved to receive antennae, then hind tarsus with four segments



51 (50).

Labrum not externally visible; abdomen with 5 united sterna



Labrum free and visible; abdomen with 3, 4 or 5 sterna united



52 (51).

Antennae indistinctly to distinctly clubbed; apex received in margined cavity on postero-lateral portion of hypomeron, just anterior to retracted foreleg; metasternum with or without oblique margined groove for middle tarsus; prosternum with click mechanism hidden by plate-like ventral surface of postcoxal intercoxal process which fits tightly against exposed portion of middle coxal cavity; elytra strongly striate and covered with silky, subrecumbent setae; abdomen with 5 united sterna; body length 1 to 5 mm




Antennae variable, but not clubbed; antennal groove, if present, at or near sternopleural suture; metasternum without margined groove for middle tarsus; IF click mechanism hidden as above, THEN elytra not strongly striate, and setae suberect; abdomen with 3 or 4 sterna united; body length 1 to 60 mm



53 (50).

Middle coxal cavities closed laterally, with mesosternum and metasternum meeting lateral to middle coxa OR antennae elongate, segments 3-8 with long rami, 9-11 flattened, elongate-serrate, pronotum often hood-like, covering head from above



Middle coxal cavities open laterally, with mesosternum and metasternum separated lateral to middle coxa by mesepimera or mesepimera and mesepisternum; antennae not as above; pronotum variable



54 (53).

Hind trochanter cylindrical, short to long, squarely attached to femur, distinctly separating coxa and tibia

ANOBIIDAE (in part)


Hind trochanter short, triangular, obliquely attached to femur so that femur and coxa are adjacent or narrowly separated on one side



55 (53).

Anterior margin of scutellum with abrupt, carinate elevation that fits against posterior margin of pronotum, or scutellum absent or not visible



Anterior margin of scutellum not abruptly elevated, fitting under overlapping posterior margin of pronotum



56 (55).

Fore coxae strongly and distinctly projecting ventral to prosternum, one-third or more of dorso-ventral length ventral to intercoxal process; fore coxae usually conical or transversely conical



Fore coxae not or weakly projecting ventral to prosternum; if fore coxae conical, then lying longitudinally and not or weakly projecting ventrally, ventral of intercoxal process



57 (56).

Tarsi with 4 distinct segments; hind coxal plates greatly expanded, hiding most of first visible abdominal sternum; hind wing, when developed, often fringed with long setae; body length 0.7 to 2 mm



Tarsi with 5 distinct segments; hind coxal plates distinct, but not hiding most of first visible abdominal sternum; hind wing not fringed; body length variable



58 (57).

Antenna with distinct, simple club of 3 segments



Antenna variously constructed, but without a simple club of 3 compact segments



59 (58).

Elytra truncate; pygidium sclerotized and completely or nearly completely exposed



Elytra complete; pygidium not sclerotized, complete covered or with only small portion exposed



60 (59).

Upper surface of body glabrous; body contractile; fore tibia held anterior to fore femur and covering antenna in hypomeral cavity when contracted

(Subfamily Orphilinae)


Upper surface of body variously pubescent, setose or scaled; body not strongly contractile: fore tibia held posterior to fore femur and antennal club not covered by leg when contracted



61 (58).

Base of pronotum crenulate; scutellum usually medially notched on anterior margin; antennal insertion not elevated; mandibles moderate and evenly curved; labrum large, sclerotized and dorsal to mandibles




Base of pronotum simple; anterior margin of scutellum not notched; dorsal margin of antennal insertion elevated and protuberant; mandibles large, abruptly curved inwardly at nearly a right angle; labrum either short and membranous, or extending between and below mandibles



62 (56).

Head with single median ocellus



Head without ocellus



63 (62).

Antennae short, not reaching middle of pronotum, first two segments relatively large, together one-third or more of total length; rest of antennal segments transverse; body covered with dense tomentum



Antennae short to long, first two segments not on-third of total length; rest of antennal segments variable; body vestiture variable



64 (63).

Head distinctly prognathous, mandibles strongly projecting forward; fore femur inclined medially and armed externally with strong spines; middle tarsus with 4 segments



Head distinctly hypognathous, mandibles either directed ventrally or hidden; fore femora simple, neither widened medially nor armed with large spines; middle tarsus with 5 segments



65 (63).

Head with subgenal ridges that fit against fore coxae when head deflexed

SCIRTIDAE (in part)


Head without subgenal ridges, genae not in contact with fore coxae



66 (65).

Basal two abdominal sterna united, either with suture between them partially obliterated medially OR if suture between them not medially indistinct, THEN sternopleural sutures at least moderately grooved to receive antennae



All abdominal sterna free, OR 3 to 5 of them united; sternal and sternopleural sutures variable



67 (66).

Suture between basal two abdominal sterna distinct medially; middle tarsus with small, bisetose empodium; antennae filiform to distinctly clubbed; body strongly convex



Suture between basal two abdominal sterna weak to absent medially; middle tarsus lacking visible empodium; antennae usually serrate, pectinate or flabellate; body weakly dorso-ventrally flattened



68 (66).

Legs retractile, rotated forward in repose, with tibia held anterior to femur; fore femur with flange on posterior face covering tibial excavation, fore tibia grooved to receive tarsus; usually with margined excavations on propleuron, mesosternum, and abdominal sterna to receive legs



If legs retractile, fore tibia held posterior to or ventral to femur; fore femoral flange, if present, located on anterior face



69 (68).

Mentum strongly sclerotized, expanded, covering labium and maxillae; head not deflexible; antennae covered by forelegs in broad sternopleural pocket; basal two abdominal sterna excavate for hind leg; middle tibia with marginal spines; body length 4 to 9 mm



Mentum normal, head usually retractable into pronotum up to anterior margin of eyes; antennae received in internal pronotal cavities or partly in sternopleural grooves and partly under legs against hypomeron; excavation for hindlegs, if present, limited to first visible abdominal sternum; margin of middle tibia not spinose; body length 1 to 2 mm



70 (66).

Elytra with thumb-like process on inner lateral surface near subapical curve, locking into 5th visible abdominal sternum; this character visible when elytra are separated from side of abdomen



Elytra without such a locking device



71 (70).

Propleuron extended toward middle of body behind fore coxae for approximately half length of trochantin; body length 10 to 15 mm



Margin of propleuron curved laterally posteriorly, not extended toward middle of body behind fore coxae; body length 1 to 8 mm



72 (55).

Head with subgenal ridges that fit against fore coxae when head deflexed; prosternum in front of coxa narrow, shorter than intercoxal process

SCIRTIDAE (in part)


Head without subgenal ridges, genae usually not in contact with fore coxae; prosternum in front of coxae nearly as long as or longer than intercoxal process



73 (72).

Hind coxal plates large, plate-like, longer medially than metasternum, hiding most of hind femur, even when fully extended



Hind coxal plates narrow, forming either a parallel plate or simple carina; hind femur fully visible



74 (73).

Elytra with 9 or 10 punctate striae; posterior portion of hypomeron extending up to half the distance to mesal edge of fore coxae; body length 7 to 14 mm

AGYRTIDAE (in part)


Elytra without punctate striae, otherwise variable, irregularly punctate, with complex low sculpture, or up to 3 carinate costae; posterior portion of hypomeron not extending behind fore coxae or extending only a short distance mesad of lateral edge of coxa; body length 7 to 45 mm

SILPHIDAE (in part)


75 (46).

Hind coxae widely separated by broad, truncate intercoxal process of first abdominal sternum



Intercoxal process of first abdominal sternum absent, acute or rounded



76 (75).

Middle coxal cavities open laterally, closure involving mesepisterna

(Subfamily Georissinae)


Middle coxal cavities open or closed; if open, closure solely involving mesepimeron



77 (75, 76).

Antennae geniculate, club usually of 3 segments; elytra short and truncate, exposing 2 non-flexing abdominal terga; body compact



Antennae not obviously geniculate, clubbed or not; elytra rarely exposing 2 abdominal terga, IF 2 terga exposed, THEN exposed abdominal segments flexible, body not oval or body cylindrical and compact



78 (77).

Fore legs with exposed trochantin



Fore legs with trochantin concealed or absent



79 (78).

Hind coxa extending laterally to reach elytral epipleuron or side of body, no visible contact between metathorax and first abdominal sternum



Hind coxa not reaching elytron, first abdominal sternum and metathorax visible and in contact lateral to coxa



80 (79).

Hind tarsus with 5 segments



Hind tarsus with 4 segments



81 (80).

Head with temples and occipital ridge distinct, occipital ridge closely fitting against pronotum, constricted behind to a distinct neck (difficult to see when head is retracted with ridge and temples against pronotum); elytra with strong characteristic sutural striae, no other striae evident; antennal 11-segmented, with gradual club apically composed of 3-4 segments; males with 5 visible abdominal sterna, females with 4 visible abdominal sterna

(Genus Colon)


Head without ridge and constricted neck that fits against pronotum; elytra striate or not, but not as above; antennae variable; with at least 5 visible abdominal sterna



82 (81).

Prosternal process between coxae distinctly elevated above level of prosternum, apex strongly curved dorsally, reaching level of postcoxal extensions of hypomeron; cervical sclerites absent; antennae not clubbed; elytra glabrous or subglabrous; body length 8 to 20 mm



Prosternal process not elevated between coxae nor with apex strongly curved dorsally; cervical sclerites present; antennae clubbed or not; elytra densely to sparsely setose, subglabrous or glabrous; body length 1 to 24 mm



83 (82).

Fore coxae not projecting distinctly below intercoxal process, large and transverse; antennae distinctly clubbed; prothorax with sharp lateral margins; IF fore coxae slightly projecting THEN antennae distinctly clubbed and tarsi not lobed beneath; not bright red



Fore coxae projecting distinctly below intercoxal process, conical or transverse; antennae variable; lateral margins of prothorax variable; IF fore coxae only slightly projecting, THEN antennae feebly clubbed, and tarsi lobed beneath AND coloration bright red



84 (83).

Tarsi with lobes on multiple segments; fore coxal cavity circular, elongate or slightly transverse; labrum subtruncate to concave or deeply emarginate; eye often emarginate; antenna usually apically clubbed, club of one or more segments; elytra often punctate-striate; pronotum and abdomen never with eversible glands



Tarsi not lobed beneath; fore coxal cavity strongly transverse; labrum subtruncate to convex, rounded or acute; eye not emarginate; antennae rarely with distinct apical club, and if so, club of 5 or more segments; elytra usually confusedly punctate; pronotum and abdomen sometimes with eversible glands

MELYRIDAE (in part)


85 (79).

Elytra short, completely exposing one or more abdominal terga



Elytra covering all of abdominal dorsum, or exposing apex of only a single tergum



86 (85)

Labial palps non-articulated; prosternal process elevated between fore, coxae, and strongly curved dorsally behind



Labial palps with 3 segments; prosternal process flat or elevated between fore coxae, but not strongly curved dorsally behind



87 (86).

Antennae 10-segmented, club of only one segment; elytra more than twice as long as wide

(Subfamily Rhizophaginae)


Antennae 10 or 11-segmented, club of 3 or more segments; elytra less than twice as long as wide



88 (85).

Middle tarsus with 4 segments; tarsal lobes, if present, small, not obscuring penultimate segment



Middle tarsus with 5 segments, fourth possible obscured by enlarged lobe of third (pseudotetramerons)



89 (88).

Body nearly spherical, capable of being rolled into a ball; mandibles resting against metasternum in retracted position

(Genus Cybocephalus)


Body flattened cylindrical, not at all spherical



90 (88).

Antennae 10-segmented, one segment involved in club

(Subfamily Rhizophaginae)


Antennae 10 or 11-segmented, if clubbed, club of 2 or more segments



91 (90).

Body extremely flattened; elytra nearly parallel-sided, disc almost perfectly flat between rounded lateral carinae running from humeri to near apex, setting off vertical sides and guttered epipleura margin; either large (over 10 mm) and red with expanded temples, or small (less than 5 mm) and dull brown without temples



Body not so distinctly flattened; elytra distinctly transversely arched, not with combination of characters as above



92 (91).

Dorsal face of mandible with tubercle that fits into cavity on clypeus, setose cavity at base, hidden when mandibles are closed (mycangium); elytra with scutellary striole; antennae with 2 or 3 segments forming club; body oval to cylindrical



Mandibles without dorsal mycangium; elytra without scutellary striole; antennae and body shape variable



93 (92).

Antennae with a distinct club AND middle and hind tarsi with equal number of segments



Hind tarsus with one fewer segments than middle tarsus; antennae distinctly clubbed or not



94 (93).

Pygidium at least partially exposed, strongly sclerotized, punctate, distinctly different from other abdominal terga; tibiae usually spinose or denticulate on external margin



Pygidium not exposed, not strongly sclerotized, similar to other abdominal terga; tibiae smooth on external margin



95 (78).

Antennal insertion concealed from above by lateral expansion of frons; AND abdominal venter with 3 basal sterna united, fourth and fifth movable, AND fore coxal cavities closed by mesad extension of the posterior portion of the hypomeron; AND fore coxal process not expanded laterally at apex to close fore coxal cavities; antennae usually 11-segmented (rarely 9- or 10-segmented)



Combination of characters not as above



96 (95).

Abdominal venter with basal 4 sterna united



Abdominal venter with fewer than 4 sterna united



97 (96).

Hind tarsus with 5 segments, first reduced and often difficult to see; basal segment of hind tarsus either hidden in apical excavation of hind tibia OR if hind tarsal insertion fully exposed, THEN basal segment of hind tarsus less than one-fourth length of second segment and obliquely attached under second (may only be visible from below in oblique distal angle); elytra covering pygidium; antenna with distinct club of 2 to 4 capitate to elongate loose segments; AND one of the following combinations: :i) head somewhat to distinctly hypognathous; pronotum hood-like, projecting anteriorly (or ventrally in some fully hypognathous species) beyond antero-lateral angles of head (Subfamilies Bostrichinae, Dinoderinae); ii) head prognathous; intercoxal process of first abdominal sternum truncate, hind coxae widely separated, hind coxa reaching elytra laterally, separating metathorax from first abdominal sternum (Subfamily Lyctinae); OR iii) head prognathous; fore coxae transversely cylindrical, projecting at sides, foreleg attached at directed laterally, femur and trochanter large (Subfamily Polycaoninae)



Tarsi with basal segment not reduced; other characters variable; if basal segment of hind tarsus reduced relative to second, pronotum not hood-like, head not hypognathous AND/OR hind tarsus 4-segmented, pygidium exposed, basal abdominal sternum not widely truncate between hind coxae; fore coxae not transversely cylindrical and projecting at sides



98 (97).

Middle tarsus with 4 distinct segments



Middle tarsus with 5 segments, or tarsi pseudotetramerous



99 (98).

Middle coxal cavities closed laterally



Middle coxal cavities open laterally



100 (99).

Antennal insertions concealed from above



Antennal insertions exposed from above



101 (100)

Genae with pair of anteriorly directed horns extending beyond labium, an visible from above



Gena lacking gular horns



102 (101).

Abdomen with 6 visible sterna; pronotum usually large, hood-like, covering or nearly covering head; pygidium usually exposed; epipleuron incomplete; frontoclypeal suture absent; body length less than 2 mm



Abdomen with 5 or 6 visible sterna; pronotum never hood-like, head visible from above; pygidium, epipleura and frontoclypeal suture variable; IF abdomen with 6 visible sterna, THEN body length 4 mm or more, and frontoclypeal suture present



103 (102).

Antennae longer, reaching to or beyond middle of pronotum, club loose; pronotum usually with pair of sublateral discal carinae or grooves, running from base, lateral of basal pits; body usually round to oval



Antennae shorter, not reaching beyond middle of pronotum, club compact; IF pronotum with discal carinae or grooves, THEN usually with a median groove or pit and body elongate



104 (103).

Posterior margin of last abdominal sternum crenulate OR body distinctly oval, length no more than twice maximum width; antennae 8-, 9- or 10-segmented; hind trochanter obliquely attached to femur, but distinctly separating coxa from femur



Posterior margin of last abdominal sternum never crenulate, antennae with 10 or 11 segments; body elongate, at least 2.75 times maximum width; hind trochanter offset, so that femur and coxa are in contact or nearly so



105 (99).

Hind coxae separated by more than half transverse coxal diameter



Hind coxae separated by less than half transverse coxal diameter



106 (105).

Fore coxal cavities narrowly closed; fore and middle coxae strongly transverse; mandible tucked into cavity when closed, not visible from side; antenna 9-segmented, last 5 segment forming club; pronotum not grooved or carinate on disc; small beetles, body length less than 2 mm

(Genus Orthoperus)


Fore coxal cavities narrowly to widely open; fore and middle coxae circular to slightly transverse; mandible visible from side; antennae 8 to 11 segmented, if clubbed, club of 1, 2 or 3 segments; pronotum usually with submarginal grooves or carinae, especially basally; body length 1 to 10 mm



107 (105)

Intercoxal process of first abdominal sternum absent, no part of sternum extending between coxae to contact metasternum; first abdominal sternum lacking margined hind coxal cavities; body soft; small triangular part of morphological abdominal sternum 2 usually visible lateral to hind coxa (i.e. sternum 1 small and divided); often brightly coloured beetles, with red, yellow or metallic blue/green markings; body length 5 to 12 mm

(Subfamily Psoinae)


Intercoxal process of first abdominal sternum complete; first abdominal sternum with margined coxal cavities; hind coxae transverse; body fully sclerotized; basal abdominal sternum closing antero-lateral angle between hind coxa and abdomen, not divided by hind coxae; never metallic; body length 0.5 to 6.5 mm



108 (107).

Body elongate-oval and somewhat cylindrical; pronotum usually very convex in transverse section, edges often directed ventrally; pronotum without basal pits or impressions; head or pronotum of male often with horns or tubercles; antennae 8- to 10-segmented, and with club of 2-3 segments; males often with pubescent median fova on first abdominal sternum; head without distinct temples or neck



Body oval to elongate-oval, usually somewhat dorsoventrally depressed; pronotum usually weakly convex transversely, edge directed laterally; pronotum with 2 basal pits or impressions lateral to scutellum (sometimes in posterior marginal groove and difficult to detect); head and pronotum without horns or tubercles; antennae 11-segmented, last 2-5 segments forming club; all abdominal sterna free, without fovea



109 (98).

Abdomen with 6 visible sterna AND hind tarsi with 5 segments; terminal segment of maxillary palp shorter and narrower than penultimate segment; body length 0.6 to 2.7 mm



Abdomen with 4 or 5 visible sterna; tarsi variable; terminal segment of maxillary palp as wide or wider than penultimate segment AND/OR as long or longer than penultimate segment; size variable



110 (109).

Abdomen with first visible sternum longer than second (measured behind coxae); elytra without punctate or impressed striae (traces of striae occasionally visible through cuticle, but not expressed on the surface); epipleura distinct in basal half, not reaching apex (usually narrowed at level of third abdominal sternum); genae carinate and projecting ventrally between eye and mentum; apex of elytra with double suture or "subapical gap" caused by wide flange of elytral coupling system; elytra complete, exposing at most tip of last abdominal tergum



Combination of characters not as above, EITHER with first visible abdominal sternum short, elytra striate, epipleura complete to apex, gena flat between eye and mentum OR elytra not covering most of pygidium



111 (110).

Hind trochanter transversely or obliquely attached to femur, distinctly separating femur from coxa



Hind trochanter obliquely attached to femur, offset so that femur abuts coxa



112 (111).

Antennal insertions close together or separated by less than half width of head behind eyes AND pronotum without lateral carinae; hind tarsus with 5 segments; hind trochanter elongate and cylindrical

(Subfamily Ptininae)


Without combination of narrowly separated antennal insertions and no lateral carina on pronotum; other characters variable



113 (112)

Pronotum with sublateral lines or grooves that extend from base forward to midpoint, often to anterior margin; head usually with sublateral lines from median margin of eye to pronotum; lateral margins of pronotum smooth, or wavy, or with few obtuse angles, that is not acutely denticulate or serrate; head not sharply constricted to form a distinct neck; body oval to elongate, subcylindrical to strongly dorso-ventrally flattened



Pronotum usually without sublateral lines that extend from base forward to midpoint; head variable; IF pronotum with sublateral lines that extend from base forward to or beyond midpoint THEN lateral margins of pronotum sharply denticulate, anterior angles acutely projecting AND/OR head sharply constricted behind small temples: body variable



114 (113).

Middle coxal cavities open laterally



Middle coxal cavities closed laterally



115 (114).

Antennae 10-segmented, distinctly clubbed; elytra shortened, exposing all of pygidium; head abruptly constricted to form neck; body length 1 to 4 mm



Combination of characters not as above



116 (115).

Body elongate, flattened; middle and hind tarsus with some number of segments; head usually with distinct temples before abruptly constricted neck; fore coxae either closed behind, or if open, elytra transversely flat or slightly concave between slight to distinctly raised interstria between stria 6 and 7; elytra with scutellary striole; base of mandible with dorsal setose pit (mycangium) hidden beneath clypeus when mandibles closed; antennae filiform with basal segment (scape) more than 3 times length of second segment (pedicel)



Hind tarsus with one segment fewer than middle tarsus; other characters variable



117 (114).

Body shining, oval and strongly convex; pronotum tightly embracing elytra; pronotum laterally at posterior with a vaguely transparent, thin flange which slides over a smooth area on base of humeral angle of elytron, this area on elytron delimited posteriorly by a thin carina; pronotum and elytra with wide propleura and epipleura, lateral margins sharp, explanate, strongly directed ventrally, so that lateral margins are far below level of fore coxa, dorsal surface forming an inverted 'U' in cross section; tarsal claw toothed or appendiculate



Body usually not evenly oval; pronotum not fitted to elytra as above, that is without flanged areas on basal angles of pronotum, or associated elytral area; lateral margins of pronotum and elytra directed sideways, rather than ventrally to lie below level of fore coxa; tarsal claws toothed only in groups with pronotum narrowed posteriorly



118 (117).

Middle and hind tarsi with same number of segments; face of head often with beaded lateral margins



Middle tarsus with one more segment than hind tarsus; face of head without lateral margins



119 (118).

Fore coxal cavities open behind; terminal segment of maxillary palp narrow and elongate; body length 9 to 11.5 mm



Fore coxal cavities closed behind by lateral expansion of the prosternal process; terminal segment of maxillary palp securiform or narrow and elongate; body length 2.9 to 4.4 mm



120 (80, 93, 111, 166, 118).

Last visible segment of abdomen forming a terminal spine; body wedge-shaped and humpbacked; head retracted to hypognathous position; hind tibia and hind tarsus usually with oblique or transverse, comb-like serrate ridges subapically on lateral faces



Abdomen not prolonged into a terminal spine; body not as above; hind tibia and hind tarsus without comb-like serrate ridges as above, but IF similar combs are present, THEN they are apical



121 (120).

Tarsal claws with a ventral blade or elongate lobe beneath; head sharply or gradually constricted behind eyes to form a distinct neck



Tarsal claws without ventral blade or elongate lobe beneath, if claw toothed or appendiculate, not with appendage 2/3 length of upper blade; head constricted or not



122 (121).

Ventral appendage of tarsal claw usually lobe-like, membranous, but occasionally blade-like and sclerotized; elytra usually meeting along suture margin to very near apex, which may be narrowly separately rounded; prothorax with lateral margin entire, separating pronotum form hypomera or prothorax lacking complete lateral margin, with pronotum and hypomera evenly rounded laterally, not separated; middle coxal cavities usually narrowly separated, occasionally contiguous; maxillae not forming sucking tube; antennae without club or with vague to distinct club of 3 segments; hind wing with well developed radial cell; if pronotal margin completely absent, antenna with a least vague indication of club in last 3 segments and middle coxal cavities narrowly separated; if elytra broadly separated and rounded, pronotum with lateral carina at base



Ventral appendage of tarsal claw blade-like, and sclerotized; elytra usually diverging along elytral suture before apex, broadly separately rounded; pronotum lacking marginal carina laterally; antennae without club of 3 terminal segments; middle coxal cavities contiguous; maxillae usually normal, but occasionally with galeae produced into a filiform sucking tube which is at least as long as mandibles; radial cell absent in hindwing; if elytra meeting on elytral suture to very near apex, then maxilla forming sucking tube

MELOIDAE (in part)


123 (121)

Base of pronotum with marginal groove that extends laterally onto hypomeron, ending in a pit near posterior margin of coxa; pronotum narrowed posteriorly, not margined laterally; head sharply narrowed behind distinct temples to form narrow neck; elytra sparsely to densely setose



Basal groove of pronotum, if present, not ending in pit on hypomeron; pronotum margined laterally or not; elytra with or without setae



124 (123)

Antennae with last 3 segments forming elongate apical club, with latter being more than half total length of antenna



Antennae not clubbed, with weak, short club with last 3 segments shorter than half total length of antenna OR with only last antennal segment long, and subequal to combined length of segments 7-10

ANTHICIDAE (in part)


125 (123).

Middle coxal cavities closed laterally



Middle coxal cavities open laterally



126 (125).

Abdomen with basal 3 visible sterna united; antennae 11-segmented, submoniliform/triangular, filiform, serrate to subflabellate; cervical sclerites present



Abdomen with none or no more than 2 basal sterna united; antennae 10- or 11-segmented; moniliform to capitate; cervical sclerites absent



127 (126).

Prothorax with pleurosternal suture ending in a large setose pit at antero-lateral margin of fore coxal cavity; abdomen with 2 basal sterna united; antennal 11-segmented; body length 1.5 to 3.8 mm



Prothorax with or without pleurosternal suture, but lacking large setose pit on anterior margin of fore coxal cavity; abdomen with all sterna free, or with 2 basal sterna united (Genus Aegialites): antennae 10- or 11-segmented; body length 1.5 to 7.0 mm; widespread in forests and Pacific beaches (Genus Aegialites)



128 (125).

Pronotum lacking lateral carina



Pronotum with complete or incomplete lateral carina



129 (128).

Hind coxae extending laterally to elytron or side of body, completely separating metepisternum from basal sternum of abdomen



Hind coxae not reaching elytron or side of body, metepisternum and basal sternum of abdomen in contact lateral to hind coxae



130 (129).

Tarsal formula 4-4-3 (actually 5-5-4, pseudotetramerous/pseudotrimerous); eyes coarsely faceted, appearing "hairy", interfacetal setae as coarse, long and dense as those on front and sides of head adjacent to eyes; body length 1 to 4 mm



Tarsal formula distinctly 5-5-4; eyes with or without interfacetal setae, IF interfacetal setae present, THEN setae not as coarse, long or obvious as on front and sides of head adjacent to eyes; body length 4 to 21 mm



131 (130).

Head prognathous, not abruptly constricted to narrow neck, and lacking distinct temples; anterior portion of prosternum as long as or longer than prosternal process; abdomen with basal 2 sterna united



Head distinctly declined, abruptly constricted to form narrow neck behind distinct temples; anterior portion of prosternum shorter than prosternal process

(Subfamily Eurygeniinae)


132 (129).

Elytra distinctly setose; eye emarginate anteriorly; penultimate tarsal segment with large lobe beneath



Elytra glabrous; eye not emarginate; penultimate tarsal segment simple

PYTHIDAE (in part)


133 (128).

Hind coxa extending laterally to elytra or side of body, completely separating metepisternum from basal abdominal sternum; middle tibiae spurs serrate, pectinate or pubescent



Hind coxa not reaching elytra or side of body, metathorax and basal abdominal sternum at least narrowly closing hind coxal cavity laterally; middle tibial spurs variable



134 (133).

Head vertically narrowed behind eyes to form narrow neck, head not received into prothorax, either bulging beyond pronotal margin, or fitting closely against pronotal margin so that head in lateral view has a posterior carina or crest meeting anterior margin of pronotum



Head gradually narrowed behind eyes, fitting into pronotum in a telescoping manner



135 (133).

Elytra with sutural and epipleural margins elevated; with strongly elevated carina running from humeral angle to near apex of elytra, resulting in distinctly concave elytral disc; pronotum with median longitudinal elevated carina on basal third, and with deep transverse grooves with pints at each end on either side of carina

(Genus Ischalia)


Elytra and pronotum without strongly elevated carinae; elytra disc convex



136 (135)

Median longitudinal line (discrimen) of metasternum short, extended form hind margin forward less than half length of sternum; middle coxae normal, convex and punctate anterior to trochanter insertion



Median longitudinal line (discrimen) of metasternum longer, extending from hind margin forward more than half length of sternum; middle coxa with unique, polished, ventral face anterior to trochanter insertion (this polished area opposed by flat surface if trochanter and base of femur when leg rotated forward)



137 (136).

Antennae short, not reaching middle of pronotum; antennae with apical 3 segments forming on distinct, rather abrupt club



Antennae longer, reaching base of elytra; antennae with apical segments somewhat wider than basal segments, but not forming abrupt club

(Genus Sphalma)


138 (1).

Head prognathous; pronotum expanded anteriorly, extending over head in retracted position, or head retractile into tubular prothorax; distinctly to slightly dorso-ventrally flattened; antenna with 9 or fewer segments; some, possibly all, bioluminescent



Head hypognathous, not retractile into prothorax; body globular-cylindrical; antennae 11-segmented; not bioluminescent