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For educational purposes only; do not review, quote or abstract:--

A Public Service on the basics of Insect Identification

 

 

Key to Families of Hymenoptera in Great Britain

 

(Derived from Borror & Delong, 1964; Borror et al., 1989; Clausen, 1940;

Gauld & Bolton, 1988; Hill, 1923 & Richards, 1977 by E. F. Legner)

 

(Email Contacts)

 

[Please refer to <Guide> for additional illustrations & <Hymenoptera> for order details]

 

     Note:  Not all illustrations are of species found in Great Britain:

 

 

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1a.    Abdomen broadly attached to thorax, no marked constriction between 1st and 2nd abdominal segments; cenchri (two rounded prominences with roughened surface to engage fore wings when folded over abdomen) present except in Cephidae, in which the first abdominal tergite is centrally divided by a membranous slit; front tibia usually with 2 apical spurs; a closed anal cell often present in fore wing; larva with continuous gut; thoracic (except Orussus) and, usually, abdominal legs present .......... Symphyta ......  Symphyta (Chalastogastra)--sawflies & horntails (Sawflies, mostly phytophagous) <General Characteristics>  (see Benson, 1951 for key to families).

 

10

1b.    Abdomen deeply constricted between 1st segment (propodeum) and 2nd (first abdominal) except in a few minute Chalcidoidea with very reduced wing venation; cenchri never present and first abdominal tergite never with a membranous slit extending to its base; fore tibia with only one apical spur with 2 in the Ceraphronoidea; fore wing with no closed anal cell; larva with rectum not connected to front part of gut before pupation (except sometimes in last instar); legs absent..........Apocrita..... Apocrita Aculeata (stinging Hymenoptera)     Apocrita..... Apocrita Aculeata (stinging Hymenoptera)    [Characteristics]

 

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2a.    Antennae with 3 segments of normal thickness, 3rd very long and made up of several fused, followed by a thread-like flagellum of at least 9 segments; head without hypostomal bridge; fore wing with Rs forked (always in British species); male genitalia inverted (= strophandrious) [in British species, normal (= orthandrious) in some American species], parameres with cupped disks and with articulation to parameral plates,,,,,, (Xyeloidea) ........ Xyelidae     (Details)

 

3

2b.    Antennae not as previously described, Rs in fore wing not forked

 

4

3a.    Antennae with 11 or more segments except in Orussidae &&, in which segment 9 is swollen and longer than any of the others; head with hypostomal bridge; male genitalia normal..................

 

9

3b.    Antennae with 10 segments or less except in Diprionidae, which have antennae serrate or comb-like (Athalia, Fenella and Heteranthrus, Tenthredinidae, may have 10-15 antennal segments but lack the following characters which are found in some or all families under couplet 4:  pronotum with hind margin straight, insect >11.0 mm. long, fore tibia with 1 (not 2) apical spur, antennae inserted below the eyes and apparent clypeus).  Head without hypostomal bridge (the Cimbicidae, in which a bridge-like condition may appear to be present, have capitate antennae); male genitalia inverted, parameres without cupping disks ............. (Tenthredinoidea)   <Overview>; <Adults> & <Juveniles>   (Details)

 

5

4a.    Antennae not inserted on ventral side of head; cenchri present; in genitalia of %%, the parameres with cupping disks and articulate to parameral plates

 

8

4b.    Either antennae inserted ventrally beneath eyes and below the apparent clypeus (Orussoidea) or cenchri absent (Cephoidea); in % genitalia, parameres without cupping disks and not articulate but fused to parameral plates

 

6

5a.    Pronotum with hind margin almost straight, the emargination being no deeper than the length of tegula; abdomen strongly flattened dorso-ventrally .............. (Megalodontoidea)

 

7

5b.    Pronotum with hind margin deeply emarginate, more deeply than length of tegula; abdomen cylindrical ............... (Siricoidea)   (Details)

 

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6a.    Antennae flabellate; fore wing without separate Sc; 2nd abdominal tergite not medially divided (uncertain British group) ............. (Megalodontoidea)  Megalodontidae   (Details)

 

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6b.    Antennae setaceous; fore wing with separate Sc; 2nd abdominal tergite divided medially (Megalodontoidea)  Pamphiliidae   (Details)

 

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7a.    Fore wing with 1st abscissa of Rs directed towards base of wing, last abscissa recurved; mesoscutum much longer than scutellum; tegula minute, hidden; neck short .............. (Siricoidea)  Siricidae    (Details)

 

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7b.    Fore wing with 1st abscissa of Rs directed towards apex of wing, last abscissa not recurved; mesoscutum hardly longer than scutellum with axillae; tegula normal though rather small; neck long .............  (Siricoidea)   (Details)   Xiphydriidae

 

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8a.   Antennae with 11 linear segments in %; 10 segments in &, with 9th large and 10th very small; no constriction between 1st and 2nd abdominal segments; fore wing with no enclosed anal cell; hind wing without cross-veins r-m or m-cu (uncertain British group) .............. (Orussoidea)  Orussidae   <Overview>; <Adults> & <Juveniles>   (Details)

 

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8b.    Antennae with 16-30 segments, filiform or slightly clavate; slight constriction between 1st and 2nd abdominal segments; fore wing with closed anal cell; hind wing with cross veins r-m and m-cu present ............... (Cephoidea)  Cephidae   (Details)

 

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9a.    Antennae with 3 segments, 3rd very long; fore wing with cross vein 2r absent .............. (Tenthredinoidea)  Argidae   (Details)

 

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9b.    Antennae with 4 segments, 3rd very long, 4th minute; fore wing with cross vein 2r present, cell IM of a peculiar pear shape  .............. (Tenthredinoidea)  <Overview>; <Adults> & <Juveniles>   Blasticotomidae

 

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9c.    Antennae with 4-5 segments followed by a very strongly marked club which may show traces of segmentation; sides of abdomen carinate; fore wing with cross vein 2r present .......... Tenthredinoidea)  Cimbicidae   (Details)

 

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9d.    Antennae typically with 9 segments, rarely with as few as 7 or with 10-15; sides of abdomen not carinate; fore wing often with cross vein 2r present ........... .(Tenthredinoidea)  Tenthredinidae   <Overview>; <Adults> & <Juveniles>   (Details)

 

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9e.    Antennae with 13 or more segments, serrate in &, comb-like in %; fore wing with cross vein 2r absent ............ (Tenthredinoidea)  Diprionidae   (Details)

 

11

10a.    Wings fully developed

 

62

10b.    Wings very much reduced or absent

 

12

11a.    Hind wings without anal or vannal lobe, except in Evaniidae, in which the abdomen is attached at the top of the propodeum, in most Braconidae, Microgasterinae, in which antennae have 18 segments and some Proctotrupidae, in which the fore wing venation is characteristic; costa of hind wing not or imperfectly developed except (apparently) in some Evanioidea and Proctotrupoidea; hind femur with a trochantellus (= an apparent 2nd segment to trochanter which is part of femur) except in some Cynipoids, Chalcidoids and Proctotrupoids; last visible tergite and sternite of & not apposed except in Proctotrupoidea, some Cynipoidea and, less distinctly, Trigonaloidea; ovipositor, which is often elongated, is partly exposed, at least in ventral view, except in Evaniidae, most Cynipoidea and most Proctotrupoidea; in the Trigonalidae the ovipositor is reduced; tergite 8 fully exposed and resembling 7 except in a few Braconidae and Proctotrupoidea ............ Apocrita -- Parasitica   (Details)

 

42

11b.    Hind wing with an anal or vannal lobe, except in Formicidae, in which the segment of the abdomen formes a scale or node and in % Mutillidae which have a felt line  on the 2nd abdominal tergite and in the Vespinae; the lobe is defined only by a small excision in the Chrysididae and Cleptidae; costal vein of hind wing often developed; hind femur without a trochantellus though in a few groups the base of femur may be ringed by a sulcus; last visible tergite and sternite of & apposed, except in Ceropales (Pompilidae) and a few parasitic bees (e.g., Melecta); ovipositor (sting) entirely hidden, tergite 8 retracted and partly desclerotized (except Dryinidae); antennae with 13 segments or less .............. Apocrita-- Aculeata    (Details)

 

17

12a.    Abdomen attached near top of propodeum; fore wing with costal cell wide, pterostigma present; hind wing with a strong vein along its fore margin and with no enclosed cells (sometimes one such cell in non-British species); abdomen with spiracles on segments 1 & 8, pygostyles present; antennae with 13-14 segments ............. (Evanioidea)   <Overview>   (Details)

 

13

12b.    Abdomen normally attached near bottom of propodeum (if attached about 1/2 way up the propodeum (= Cenocaelius and Paxylomma of Braconidae), the costal cell in fore wing is obliterated

 

14

13a.    Fore wing with pterostigma and antennae usually with more than 16 segments, scape short (except Streblocera).  Hind wing with at least 2 enclosed cells except Neorhacodes (Ichneumonidae, Fig. A) and some Braconidae, which have the costa and radius fused in fore wing up to the pterostigma and sometimes ca. 20 antennal segments or (Paxylomma) the first 2 segments of abdomen much longer than broad and the hind basitarsus thickened; trochantellus distinct, at least on hind leg; spiracles on abdominal segments 1-8, or Braconidae, Sigalphinae (Chelonus, etc.) 1-6; pygostyles present

 

15

13b.    Antennae with not more than 16 segments; fore wing with no true pterostigma except in Heloridae and Proctotrupidae, in which the costal cell is wide, and the Ceraphronidae, in which the axillae are on the same level as the central part of the scutellum; venation generally reduced; hind wing with no enclosed cells except in some Diapriidae and Ibaliidae, in which either the head is greatly produced forwards or the costal cell of the fore wing is wide; trochantellus often indistinct or absent; in && tergites 9 & 10 indistinguishably fused, except in some Proctotrupidae and Ceraphronidae

 

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14a.    Fore wing  with costal cell wide, Rs + M complete and cross veins 3r-m, 2r-m, Rs and 2m-cu present; tarsi with plantar lobes; last visible tergite and sternite almost apposed, ovipositor reduced and hidden, abdominal tergite 9 in && retracted with the central part membranous; tergite 10 not separately developed; mandibles with 4 large teeth on the right, 3 on the left one; antennae with more than 20 segments in the one British species)  ........... (Trigonaloidea)  Trigonalidae   <Habits>; <Adults> & <Juveniles>   (Details)

 

19

14b.    Fore wing with costal cell almost or quite obliterated, at least one of cross-veins 3r-m, 2r-m, Rs and 2m-cu absent; tarsi without plantar lobes; last visible tergite and sternite of & abdomen not clearly apposed, ovipositor usually clearly exserted and abdominal tergite 9 often not retracted .............. (Ichneumonoidea)   <Overview>   (Details)

 

20

15a.    Either fore wing with well-developed costa or the edge of abdomen sharp and curved downwards, or head much produced forwards and antennae inserted on shelf-like process; pronotum either obtuse below but with a narrow posteroventral process which meets its opposite from the other side beneath the fore coxae, or pronotum is fully coadapted to mesepisternum; abdomen rarely compressed, spiracles on abdominal segments 1, 1 & 8, or 1-6; last visible tergite and sternite of & apposed, pygostyles present; ovipositor hidden except in Proctotrupidae, in which it projects inside the enlarged pygostyles; antennal scape usually long, if short then a pterostigma present ............. Proctotrupoidea   <Overview>   (Details)

 

16

15b.    Fore wing with no pterostigma; proximal part of costa not developed, except weakly in Ibaliidae, which have a short antennal scape; abdomen with spiracles on segments 1 & 8, last visible tergite and sternite of & not apposed; ovipositor exposed, at least below, except in most Cynipoidea in which abdomen is usually compressed laterally

 

26

16a.    Pronotum lateroventrally pointed and closely coadapted to mesepisternum, posteriorly extending back to tegulae; fore wing with cell R-1 mostly complete; antennae with scape short and with 12-16 segments; trochantellus usually not developed; abdomen in & with tergite 9 retracted and desclerotized; abdomen usually compressed laterally, pygostyles absent ............. (Cynipoidea)  

  <Overview>   (Details)   [See Subfamilies]

 

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16b.    Pronotum lateroventrally rounded, not closely coadapted to mesepisternum, posteriorly usually distinctly separated from tegulae; fore wing with cell R-1 not defined by proper veins or absent; antennal scape usually long (not clearly so in some Mymaridae); antennae with 13 segments or less; trochantellus often present; abdomen rarely compressed, with pygostyles in & central portion of tergite 9 exposed and pigmented .......... (Chalcidoidea)   <Overview>    (Details)

 

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17a.    Hind wing with anal lobe; fore wing not longitudinally folded, cross vein 2m-cu and 2r-m absent; antennae inserted well above clypeus, with 13 segments; abdomen  short, compressed, with a long, abrupt petiole and a short, often hidden, ovipositor; propleura not meeting dorsally and forming a neck ............ (Evanioidea)  Evaniidae   <Habits>; <Adults> & <Juveniles>   (Details)

 

18

17b.    Hind wing with no anal lobe; antennae with 13 segments in %, 14 in &; abdomen long, gradually clavate, ovipositor exserted, often long; propleura meeting above and forming a neck

 

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18a.    Fore wing not longitudinally folded, with cross veins 2m-cu and 2r-m present; antennae inserted just above clypeus ............... (Evanioidea)  Aulacidae  <Habits>; <Adults> & <Juveniles>    (Details)

 

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18b.    Fore wing longitudinally folded, with cross veins 2m-cu and 2r-m absent; antennae inserted well above clypeus  ............ (Evanioidea)  Gasteruptiidae   <Habits>; <Adults> & <Juveniles>   (Details)

 

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19a.    Fore wing  with cross vein 2m-cu almost invariably present; Rs+M interrupted; hind wing with cross vein r-m meeting Rs after that vein leaves Sc+R (including Agriotypus and Neorhacodes; the latter would key to the Braconidae but the fore wing  is characteristic) ............... (Ichneumonoidea)  Ichneumonidae   <Habits>; <Adults-1> & <Adults-2> & <Adults-3>; & <Juveniles>

 

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19b.    Fore wing  without cross vein 2m-cu; hind wing  with cross vein r-m meeting Sc+R before the separation of Rs (includes Alysiinae, Aphidiinae and Paxylommatinae) .......... (Ichneumonoidea)  Braconidae   <Habits>; <Adults-1> & <Adults-2> & <Adults-3>

 

21

20a.    Sides of abdomen acute or distinctly margined; antennae with not more than 12 segments; front tibia with one spur ........... (Proctotrupoidea)  Scelionidae   <Habits>; <Adults> & <Juveniles>

 

22

20b.    Sides of abdomen rounded of if, in some Belytinae, more acute, the antennae have 14-15 segments

 

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21a.    Antennae with 10 or rarely fewer segments; fore wing without marginal or stigmal veins, often also without submarginal vein  .......... Proctotrupoidea) ...... Platygastridae   (= Platygasteridae) <Habits>; <Adults> & <Juveniles>

 

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21b.    Antennae with 11 or 12 segments, or with 7-8 and an unsegmented club; if with 10, stigmal vein present ........... (Proctotrupoidea)  Scelionidae   <Habits>; <Adults> & <Juveniles>

 

23

22a.    Fore tibia with 2 spurs; antennae inserted very low down, at clypeal margin, with 9-11 segments, scape very long; radial cell in fore wing not enclosed, pterostigma sometimes developed; scutellum usually with a frenum and with axillae in same plane as main surface ............... (Ceraphronoidea)   <Overivew>   (Details)

 

24

22b.    Front tibia with one spur; antennae inserted near middle of face, with 11-15 segments, scape usually short; radial cell in fore wing normally closed; scutellum without a frenum and axillae not in same plane as main surface ............. (Proctotrupoidea)   <Overview>    (Details)

 

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23a.    Tibial spurs 2, 1, 2; all spurs comb-like; large one of fore tibia not 2-forked; antennae with 9-10 segments in && and 10-11 in %%; abdominal petiole visible as a short ring, tergite 6 with oval patch of dense reticulation ............. (Ceraphronoidea)  Ceraphronidae   <Habits>; <Adults> & <Juveniles>

 

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23b.    Tibial spurs 2, 2, 2; the large, comb-like one of fore tibia, forked; antennae with 11 segments in both sexes; abdominal petiole shorter, usually hidden by the next segment, tergite 6 without a patch of dense reticulation ............. (Ceraphronoidea)  Megaspilidae   <Habits>; <Adults> & <Juveniles>

 

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24a.    Fore wing  with no true pterostigma, though the parastigma is sometimes thickened or else the abdomen is long petiolate; antennae with 11-15 segments inserted  far above clypeus on a frontal shelf or strong prominence [except in Ismarus in which they are inserted normally at about the middle of face, but this genus has venation of forewing much as in Fig. A and an enclosed cell in the hind wing] ............. (Proctotrupoidea)  Diapriidae   <Habits>; <Adults> & <Juveniles>

 

25

24b.    Fore wing with a pterostigma; antennae not inserted on a frontal shelf, usually nearer clypeus or at middle of face

 

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25a.    Antennae with 15 segments; venation  characteristic; abdomen long, petiolate  ............ (Proctotrupoidea)  Heloridae   <Habits>; <Adults> & <Juveniles>

 

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25b.    Antennae with 13 segments, inserted at middle of face, scape short; fore wing with a closed, normally very small, radial cell; ovipositor long ........... (Proctotrupoidea)  Proctotrupidae   (= Serphidae) <Habits>; <Adults> & <Juveniles>

 

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26a.    Larger species, cell R-1 closed in fore wing and 9X as long as broad; hind basitarsus 2X as long as remaining segments together; largest segment of abdomen one of 4-6, two or more small tergal plates preceding the large one ......... (Cynipoidea)  Ibaliidae   <Habits>; <Adults> & <Juveniles>

 

27

26b.    Smaller species, cell R-1 not always fully closed, less elongated; hind basitarsus normal; largest segment of abdomen 2 or 3, or these fused, at most one small tergal plate preceding the large one

 

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27a.    Rs+M, when present in fore wing, directed towards M+Cu rather than Sc+R; if the 2nd or 3rd tergites are long and form half the abdomen, the scutellum has an apical cup-like depression;

abdomen sometimes long petiolate (Includes Eucoilinae & Anacharitinae) ............... (Cynipoidea)  Figitidae   <Habits>; <Adults> & <Juveniles>

 

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27b.    Rs+M, when present in fore wing, directed towards the mid point between M+Cu and Sc+R; 2nd or 2nd & 3rd tergites usually the largest and forming 1/2 of abdomen, which is never long petiolate  (includes Charipinae)............ (Cynipoidea)  Cynipidae   <Habits>; <Adults> & <Juveniles>

 

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28a.    Hind wings linear, base forming a stalk, wings with long fringes; ovipositor sometimes issuing almost at tip of abdomen; antennae without annelli (includes Mymaromminae) ............ (Chalcidoidea)  Mymaridae   <Habits>; <Adults> & <Juveniles>

 

29

28b.    Not as previously described

 

30

29a.    Axillae advanced strongly in front of anterior margin of scutellum and usually in front of tegulae; tarsi usually with 3-4 segments

 

33

29b.    Axillae not or little advanced in front of anterior margin of scutellum; tarsi with 5 segments.

 

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30a.    Hind coxa much enlarged, hind femur compressed; tarsi with 4 segments; marginal wing vein long. ............. (Chalcidoidea)  Elasmidae   <Habits>; <Adults> & <Juveniles>

 

31

30b.    Hind coxa not enlarged

 

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31a.    Mid coxa with base lying before the mid line of mesopleuron, and lying in a groove on the under side of thorax  ............ (Chalcidoidea)  Encyrtidae   <Habits>; <Adults-1> & <Adults-2>; & <Juveniles>

 

32

31b.    Mid coxa lying well behind the mid line of mesopleuron, with no groove on the underside of the thorax

 

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32a.    Tarsi usually with 4 segments but with 5 in most Aphelininae and a few females of other groups; fore wing narrower, pubescence not in rows or lines ............ (Chalcidoidea)  Eulophidae   <Habits>; <Adults> & <Juveniles>

 

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32b.    Tarsi with 3 segments; fore wing very broad, pubescence usually in rows or lines, marginal and stigmal veins forming a single curve ........... (Chalcidoidea)  Trichogrammatidae   <Habits>; <Adults> & <Juveniiles>

 

34

33a.    Mesepisternum little sculptured, large and almost completely covering the mesepimeron  (except in some % Eupelmidae); mid tibial spur usually enlarged  (spur enlarged in the above % which have a short pronotum)

 

35

33b.    Mesepisternum not enlarged, of about the same width as the mesepimeron; mid tibial spur rarely longer than the bigger hind tibial one (except in some Cleonyminae which have a long pronotum)

 

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34a.    Mesonotum in && with center of scutum depressed or flat, notauli (= two grooves emanating from front margin of scutum) impressed at least anteriorly and usually long; males with scutum usually convex and notauli often much shorter but in them the mesepisternum is not enlarged; marginal vein of fore wing long .............. (Chalcidoidea)  Eupelmidae   <Habits>; <Adults> & <Juveniles>

 

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34b.    Mesoscutum somewhat convex, notauli not more than feebly indicated; mesepimeron enlarged; marginal vein in fore wing as long as submarginal; scutellum transversely linear; mid tibia with long bristles ............. (Chalcidoidea)  Encyrtidae & Signiphoridae (= Thysanidae)

 

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35a.    Mandibles sickle-shaped, usually with 1-2 inner teeth; thorax very convex, scutellum usually produced backwards; abdomen compressed, usually with a long petiole (uncertain British group) ............ (Chalcidoidea)  Eucharitidae   <Habits>; <Adults> & <Juveniles>

 

36

35b.    Mandibles stout, with 3-4 teeth at apex; thorax rarely convex

 

37

36a.    Hind coxa large, 2-3X longer than front one

 

39

36b.    Hind coxa not so conspicuously longer than front one

 

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37a.    Hind femur with a row of teeth beneath ........... (Chalcidoidea)  Chalcididae   <Habits>; <Adults> & <Juveniles>

 

38

37b.    Hind femur with at most one tooth beneath

 

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38a.    Notauli present; abdomen not coarsely punctured, ovipositor usually long and exserted ........... (Chalcidoidea)  Torymidae  (except Megastigminae)   <Habits>; <Adults> & <Juveniles>

 

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38b.    Notauli very faint or absent; abdomen usually with rows of coarse punctures, ovipositor short ............. (Chalcidoidea)  Ormyridae   <Habits>; <Adults> & <Juveniles>

 

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39a.    Pronotum short, transversely linear, or elongated but much narrowed in front; mesoscutum usually reticulate; usually metallic insects (including Miscogasterinae, Spalangiinae and Cleonyminae; the elongated pronotum and flattened dorsal side of abdomen in the last named subfamily are sometimes regarded as family characters) ............. Chalcidoidea)  Pteromalidae   <Habits>; <Adults> & <Juveniles>

 

40

39b.    Pronotum wide, quadrate, scarcely narrower than mesoscutum, which is often coarsely punctured

 

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40a.    Stigmal vein thickened into a very large knob, if not thickened, still with ovipositor elongated; otherwise rather like Eurytomidae ............. (Chalcidoidea)  Torymidae  (Megastigminae)   <Habits>; <Adults> & <Juveniles>

 

41

40b.    Stigmal vein not so thickened; ovipositor short

 

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41a.    Abdomen in %% long petiolate and antennae somewhat verticillate; abdomen in && rounded or ovate, somewhat compressed, 2nd tergite never very large, last sternite usually produced; black or yellowish insects .............. (Chalcidoidea)  Eurytomidae   <Habits>; <Adults> & <Juveniles>

 

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41b.    Abdomen small, subtriangular, short petiolate, 2nd or fused 2nd and 3rd tergites covering most of its surface; antennae not verticillate; thorax large but short; somewhat metallic insects  ........... (Chalcidoidea)  Perilampidae   <Habits>; <Adults> & <Juveniles>

 

49

42a.    Hind wings with no cells enclosed by veins; pronotum obtuse below and not closely coadapted to mesepisternum; abdominal spiracles on segments 1-7 or 1-8 (Dryinidae); both sexes have same number of antennal segments ..............  Chrysidoidea (= Bethyloidea)   <Overview>   (Details)

 

43

42b.    Hind wing with one or more cells enclosed by veins; abdominal spiracles on segments 1-8; nearly always more antennal segments in than in previous

 

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43a.    Hind wing without an anal lobe and first segment of abdomen forming a scale or node, or the first 2 segments nodiform and the 2nd segment deeply separated from the third both above and below ............  Vespoidea (= Formicoidea)  Formicidae   <Habits>; <Adults> & <Juveniles>

 

44

43b.    Hind wings with an anal lobe except in Mutillidae, in which there is a felt line  at the side of the 2nd abdominal segment; 1st segment of abdomen not scale-like; if nodiform, then the next segment is closely coadapted to the 3rd

 

45

44a.    Pronotum produced back to or almost to the tegulae with no conspicuous lobe concealing the anterior thoracic spiracle

 

48

44b.    Pronotum not produced back to the tegulae but usually forming at a lower level a conspicuous lobe over the anterior thoracic spiracle

 

46

45a.    Fore wing  usually (always in British species) longitudinally folded in repose, cell M+Rs+M long, longer than cell M; glossa and paraglossa ending in pigmented pads; eyes emarginate .......... (Vespoidea)   <Overview>   (Details)

 

47

45b.    Fore wing not longitudinally folded in repose, cell M+Rs+M shorter; glossa and paraglossa without pads; eyes usually not emarginate

 

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46a.    Mandibles long, crossing one another when at rest; mid tibia with one spur; tarsal claws 2-forked; hind wing with an anal lobe; solitary species ............. (Vespoidea)  Eumenidae   <Habits>; <Adults> & <Juveniles>

 

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46b.    Mandibles short and broad, lying transversely, one above the other; mid tibia with 2 spurs; tarsal claws simple; hind wing (in Vespinae) with no anal lobe; social species ........... (Vespoidea)  Vespidae   <Habits>; <Adults> & <Juveniles>

 

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47a.    Mesopleuron divided obliquely by a suture running from near upper posterior corner, downwards and forwards; pronotum obtuse below and loosely overlapping mesopleuron; legs long, hind femur especially so .......... (Pompiloidea)  Pompilidae   (= Psammocharidae) <Habits>; <Adults> & <Juveniles>

 

53

47b.    Mesopleuron not so divided; pronotum usually acute below (not in Tiphia) and coadapted to mesopleuron; legs usually short and stout ............ (Scolioidea)  <Overview>] [formerly Pompiloidea <Overview>]  

 

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48a.    Pubescence simple; hind tarsi not broadened .............. (Sphecoidea)  Sphecidae   <Habits>; <Adults> &  <Juveniles>

 

55

48b.    Pubescence, at least in part (e.g., near anterior thoracic spiracles), plumose or branched; hind tarsi usually somewhat widened and often densely pubescent ............ (Apoidea)   <Overview>   (Details)

 

50

49a.    Antennae with 10 segments

 

51

49b.    Antennae with 12-13 segments

 

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50a.    Antennae not inserted on a prominence but near to dorsal margin of clypeus; female with chelate fore tarsi  (except Aphelopus), sometimes apterous or brachypterous ........... (Bethyloidea)  Dryinidae   <Habits>; <Adults> & <Juveniles>

 

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50b.    Antennae inserted on a prominence high above clypeus; female apterous; male winged with relatively complete venation ............ (Bethyloidea)  Embolemidae   <Habits>; <Adults> & <Juveniles>

 

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51a.    Abdomen with 7 exposed segments; rarely metallic insects (in Britain); pronotum usually parallel-sided; head somewhat prognathous ............ (Bethyloidea)  Bethylidae   <Habits>; <Adults> & <Juveniles>

 

52

51b.    Abdomen with 3-5 exposed segments; largely metallic insects (always in British species); head orthognathous; antennae with 13 segments

 

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52a.    Abdomen with 3 exposed segments, venter concave; pronotum short but wide; propodeum normally with sharp lateral keels or teeth; sculpture usually coarse ............. (Bethyloidea)  Chrysididae  (Chrysidinae)   <Habits>; <Adults> & <Juveniles>

 

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52b.    Abdomen with 4-5 exposed segments, venter slightly convex; pronotum elongated, somewhat narrowed anteriorly; sculpture finer; not metallic insects  ........... (Bethyloidea)  Chrysididae  (Cleptinae)   <Habits>; <Adults> & <Juveniles>

 

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53a.    Second abdominal tergite with lateral felt lines; female apterous; male hind wing without anal lobe (forewing in Fig. B); body usually well punctured and with conspicuous patches of pubescence ............ (Tiphioidea) [Now in Vespoidea] Mutillidae  (= now in Sapygidae)  <Habits>; <Adults> & <Juveniles>]

 

54

53b.    Second abdominal tergite without lateral felt lines; male hind wings with an anal lobe and body often smooth, shining and nearly bare

 

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54a.    First and 2nd abdominal tergites not separated by a constriction, 1st and 2nd sternites with only a feeble constriction between them; mesosternum simple; female winged ............ (Tiphioidea)   [Now in Vespoidea]  Sapygidae   <Habits>; <Adults> & <Juveniles>

 

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54b.    First and 2nd abdominal segments separated by a deep constriction  and/or the mesosternum with 2 laminae which overlie or project between the bases of the mid coxae; female often apterous (includes Methochinae & Myrmosinae) ............. (Tiphioidea)   [Now in Vespoidea] Tiphiidae   <Habits>; <Adults> & <Juveniles>

 

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55a.    Antennal socket connected with fronto-clypeal suture by 2 sutures; glossa acute, labial palpi with segments equal or the first alone, elongated and flattened; mid coxa externally much shorter than distance from its summit to posterior wing base (as in Fig. B); females and many males with a pygidial area ............. (Apoidea)  Andrenidae   <Habits>; <Adults> & <Juveniles>

 

56

55b.    Antennal socket connected with fronto-clypeal suture by a single suture; labial palpi variable but rarely with first segment alone elongated

 

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56a.    Fore wing with first sector of M curved; labial mentum and submentum virtually absent; labial palpi usually with all segments similar; mesepisternum usually with a complete anterior oblique suture; metanotum horizontal; mid coxa externally much shorter than distance from its summit to

posterior wing base .............. (Apoidea)  Halictidae   <Habits>; <Adults> & <Juveniles>

 

57

56b.    Fore wing with first sector of M straight; labial mentum and submentum present

 

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57a.    Glossa bilobed; labial submentum elongated, not -V-shaped; anterior oblique suture present on mesepisternum; mid coxa externally much shorter than distance from its summit to posterior wing base  ............. (Apoidea)  Colletidae   (= Hylaeidae)  <Habits>; <Adults> & <Juveniles>

 

58

57b.    Glossa acute, often elongated; labial submentum V-shaped; anterior oblique suture very rarely complete, usually absent

 

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58a.    Labial palpi with segments similar and cylindrical; galea short; mid coxa, except in Macropis, much shorter than distance from its summit to posterior wing base ........... (Apoidea)  Melittidae   <Habits>; <Adults> & <Juveniles>

 

59

58b.    Labial palpi with first two segments elongated and sheathing; galea very elongate; mid coxa, except in a few parasitic Apidae, 2/3rds as long as distance from its summit to posterior wing base

 

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59a.    Labrum longer than broad and widened to a broad articulation with clypeus; subantennal suture at outer edge of socket; fore wing with two submarginal cells, usually of about the same length; last abdominal tergite nearly always without a pygidial area; scopa (= dense brush of hairs), when present, on abdominal sternites ............ (Apoidea)  Megachilidae   <Habits>; <Adults> & <Juveniles>

 

60

59b.    Labrum usually broader than long; if not, narrowed basally to a short articulation with clypeus; subantennal suture at inner edge of socket; fore wing usually with 3, rarely with 2 or 2 submarginal cells; if 2, the second is usually much shorter than first; pygidial area often present; scopa, when present, on hind legs, rarely also on abdominal sternites

 

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60a.    Scopa of female forming a pollen basket on the hind tibia and inner apical margin of tibia with a comb (except in Psithyrus); pygidial plate absent; social species ............. (Apoidea)  Apidae   <Habits>; <Adults> & <Juveniles>

 

61

60b.    Scopa of female not forming a pollen basket on the hind tibia which has no apical comb

 

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61a.    Pygidial plate nearly always present in && and usually in %%; clypeus protruberant, lateral portions seen from below bent posteriorly and lying parallel to long axis; fore coxa a little broader than long ............ (Apoidea)  Anthophoridae   (= Nomadidae) <Habits>;  <Adults> & <Juveniles>

 

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61b.    Pygidial plate absent; clypeus not protruberant, lateral portions seen from beneath transverse rather than longitudinal; fore coxa transverse ........... (Apoidea)  Anthophoridae (= Xylocopidae)   (= Nomadidae) <Habits>;  <Adults> & <Juveniles>

 

63

62a.    Abdominal sternites very membranous, tending to dry into a longitudinal fold; antennae often multiarticulate

 

64

62b.    Abdominal sternites fully sclerotized

 

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63a.    Abdomen with tergites 2 & 3 fused, not overlapping, its petiole usually broad, if narrow then its dorsal surface is straight in profile (either a circular space between clypeus and mandible, as in Fig. A, or mandibles exodont as in Fig. B); tegulae present ........... (Ichneumonoidea)  Braconidae   <Habits>; <Adults-1> & <Adults-2> & <Adults-3>  &  <Juveniles>

 

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63b.    Abdomen with tergites 2 & 3 usually separate and overlapping; if fused, the abdomen is long petiolate and the dorsal surface of the petiole is curved in profile; no circular space between clypeus and mandibles, latter not exodont; tegulae often absent ............. (Ichneumonoidea)  Ichneumonidae   <Habits>; <Adults-1> & <Adults-2> & Adults-3>; & <Juveniles>

 

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64a.    First or 1st and 2nd segments of abdomen scale-like or nodiform, distinctly separated from posterior part of abdomen .............. (Formicoidea)  Formicidae   <Habits>; <Adults> & <Juveniles>

 

65

64b.    Abdominal petiole not scale-like nor composed of 2 nodiform segments

 

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65a.    Head pear-shaped, long axis vertical, the 10-segmented antennae, which are as long as whole body, arise from a prominence; abdomen not long petiolate; females ........... (Bethyloidea)  Embolemidae   <Habits>; <Adults> & <Juveniles>

 

66

65b.    Head formed differently or otherwise not as previous

 

28

66a.    Pronotum does not extend back to the tegulae; tegulae absent in some Trichogrammatidae, but these have only 3 tarsal segments; pronotum not coadapted to the mesepisternum which has a distinct postspiracular sclerite ............ (Chalcidoidea)   <Overview>   (Details)

 

67

66b.    Pronotum extends back to tegulae if these are present; tarsi always with 5 segments; postspiracular sclerite not distinctly developed

 

68

67a.    Antennae with 10 segments or less

 

69

67b.    Antennae with >10 segments

 

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68a.    Females with chelate fore tarsi  and 10 antennal segments; pronotum not coadapted to mesepisternum ............. (Bethyloidea)  Dryinidae   <Habits>; <Adults> & <Juveniles>

 

20

68b.    Fore tarsi not chelate; pronotum somewhat distinctly coadapted to mesosternum

 

27

69a.    Abdomen compressed laterally, conspicuously deeper than broad, integument (except for base) mostly smooth and shining ........... (Cynipoidea)   <Overview>   (Details)

 

70

69b.    Abdomen not compressed laterally; integument often more sculptured and pubescent

 

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70a.    Head somewhat markedly longer than broad, usually clearly prognathous; thoracic sutures usually more complete ............. Chrysidoidea (= Bethyloidea)  Bethylidae   <Habits>; <Adults> & <Juveniles>

 

71

70b.    Head somewhat less globular or at least orthognathous

 

20

71a.    Antennae not with 12 segments or, if with 12, they arise from a prominence and the abdomen is long petiolate or its sides are acutely margined

 

72

71b.    Females:  antennae with 12 segments and other characters different than previous ............ (Scolioidea)

 

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72a.    Pronotum fused to mesonotum; abdominal tergite 2 with a lateral felt line ............. (Tiphioidea)   [Now in Vespoidea] Mutillidae  (now under Sapygidae)  <Habits>; <Adults> & <Juveniles>]

 

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72b.    Pronotum separate from mesonotum; abdominal tergite 2 without a lateral felt line ........... (Tiphioidea)   [Now in Vespoidea]  Tiphiidae   <Habits>; <Adults> & <Juveniles>

 

 

REFERENCES:

 

Benson, R. B.  1951-1958.  Hymenoptera, Symphyta.  handbk. Ident. Brit. Insects 6 (2a, b & c).

 

Borror, D. J. & D. M. DeLong.  1964.  An Introduction to the Study of Insects.  Holt, Rinehart & Winston, NY.  819      p.

 

Borror, D. J., G. A. Triplehorn & N. F. Johnson.  1989.  An Introduction to the Study of Insects, 6th ed.  Saunders   Publ. Co., Phila.  875 p.

 

Clausen, C. P.  1940.  Entomophagous Insects.  McGraw-Hill Book Co., NY.  688 p.  [reprinted 1962 by Hafner  Publ. Co., NY.].

 

Gauld, I. & B. Bolton.  1988.  The Hymenoptera.  British Mus. (Nat. Hist.), Oxford Univ. Press., NY.  332 p.

    

Hill, C. C.  1923.  Platygaster vernalis Myers, an important parasite of the Hessian fly.  J. Agr. Res. 25:  31-42.

 

Richards, O. W.  1977.  Hymenoptera Introduction and Key to Families, 2nd ed.  Roy Ent. Soc., London.  100 p.