Druon Kinsey, 1937

Cuesta-Porta, Victor, Melika, George, Nicholls, James A., Stone, Graham N. & Pujade-Villar, Juli, 2022, Re-establishment of the Nearctic oak cynipid gall wasp genus Druon Kinsey, 1937 (Hymenoptera: Cynipidae: Cynipini), with description of five new species, Zootaxa 5132 (1), pp. 1-92 : 7-10

Druon Kinsey, 1937 , stat. rev.

Type species: Druon protagion Kinsey, 1937 .

Diagnosis. Asexual and sexual females known; the malar space with striae radiating from clypeus and reaching eye, malar sulcus absent; gena broadened or not behind the eye ( Fig. 1); toruli usually located above mid height of head; antenna always with 11–12 flagellomeres; mesoscutum reticulate, notaulus complete or anteriorly incomplete, mesopleuron entirely striate or striato-reticulate ( Figs. 6, 26); transscutal articulation present; lateral propodeal carinae bent outwards in mid-height or posterior 1/3 ( Fig. 29), in some cases lateral carinae inconspicuous or absent; prominent part of the ventral spine of the hypopygium variable, around 2.3–5.1× as long as broad in ventral view. On the basis of these characters, Druon is similar to some sexual and asexual Andricus species. Asexual Andricus females differ from Druon either by presenting a densely pubescent metasoma, by differences in surface sculpturing (punctures on head and/or mesoscutum and sometimes on mesopleuron), or by the subparallel lateral propodeal carinae. Sexual forms of Andricus differ from Druon by not having all the characters mentioned above; in those Andricus species the mesoscutum is rugose or partially granulate, mesopleuron (at least the speculum) smooth, and/or the prominent part of the ventral spine of the hypopygium is longer; in addition, some sexual and asexual females of Andricus have the antenna with 13 flagellomeres. The males from the two Druon species with known sexual forms have 14 flagellomeres, incomplete propodeal carinae ( Fig. 97), and the second metasomal tergum in the form of a long narrow petiole ( Fig. 98). In contrast, in male Andricus the antenna has 12–13 flagellomeres, propodeal carinae are complete and the metasoma is without a petiole. Another important character that differentiates Druon from the genus Andricus is the shape and structure of the galls. The asexual galls of Druon are always woolly aggregations on leaves (and in one species very rarely on twigs). Only a few sexual forms of Andricus , such as the Western Palearctic A. quercusramuli ( Linnaeus, 1761) , induce similar woolly aggregated galls but they are on catkins. Moreover, only sexual generation Andricus make such galls and the females differ from the new genus by their mesopleuron, which is uniformly and very delicately transversally striate, almost smooth and by the mesoscutum which is not reticulate; in Druon the mesopleuron is completely sculptured and the mesoscutum reticulated.

Redescription. Asexual female. Head, mesosoma dark brown, chestnut brown to black, rusty brown or yellowish to yellow-amber; antenna of the same colour or paler than head; metasoma dark brown to reddish brown; mouthparts, legs yellowish-brown, light brown to dark brown, with coxae always darker.

Head alutaceous, with sparse setae, denser on lower face, rounded, trapezoidal, or transverse, 1.2–1.4× as broad as high and slightly broader than mesosoma in frontal view; 2.0–2.2× as broad as long in dorsal view. Gena alutaceous, either not or broadened behind eye in frontal view, narrower than transverse diameter of eye in lateral view. Malar space alutaceous, with striae radiating from clypeus and reaching eye, malar sulcus absent ( Figs. 1, 46); eye 2.8–4.0× as high as length of malar space. Eyes parallel or slightly converging ventrally. POL 1.8–3.6× as long as OOL, OOL slightly shorter or 1.3–1.6× as long as diameter of lateral ocellus and nearly equal to LOL, all ocelli ovate, of same size ( Figs. 2, 21, 114). Transfacial distance slightly shorter or equal to height of eye; toruli located at mid-height or level with the lower half of eye; frons higher than lower face, diameter of antennal torulus 1.3–2.0× as long as distance between them, distance between torulus and eye slightly shorter or 1.2–1.5× as long as diameter of torulus; lower face smooth, alutaceous to delicately coriaceous, with white setae, with or without short delicate striae; slightly elevated median area alutaceous to delicately coriaceous, with few setae. Clypeus rounded, quadrangular or rectangular, nearly 2.0× as broad as high, smooth, glabrous, with few setae; ventrally rounded, not emarginate and without median incision; anterior tentorial pit large, rounded, distinct, epistomal sulcus distinct, clypeo-pleurostomal line well impressed. Frons uniformly alutaceous, without striae and setae, interocellar area alutaceous. Vertex, occiput and postocciput alutaceous; postgena smooth or alutaceous, with or without setae; posterior tentorial pit large, elongated, area below impressed; occipital foramen slightly shorter or as high as height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulci which strongly diverge toward occipital foramen, postgenal bridge anteriorly slightly broader than occipital foramen. Antenna longer than head+mesosoma, with 11–12 flagellomeres (in some specimens the suture between F12 and F11 hardly visible), pedicel longer than broad; flagellomeres subsequently broadening towards apical end; F1 1.6x as long as pedicel and 1.3× as long as F2; F2 1.1× as long as F3; F3=F4=F5, F5 1.1× as long as F6, F6 to F10 nearly equal in length; F11 2.1× as long as F10; placodeal sensilla on F3/F5–F11(F12).

Mesosoma slightly longer than high, with a few white setae, denser along propleuron and laterally. Pronotum smooth, with parallel striae and sparse setae laterally; propleuron smooth, glabrous. Mesoscutum uniformly and entirely reticulate, with a few white setae along notauli ( Fig. 7), slightly longer than broad (greatest width measured across mesoscutum level with base of tegulae). Notaulus usually complete, in some species indistinct in anterior 1/3, impressed in posterior 2/3 of mesoscutum length, notaulus alutaceous or smooth; posteriorly strongly converging; anterior parallel line invisible or indistinctly impressed and extending to 1/3 of mesoscutum length; parapsidal line marked with broad impressed area; median mesoscutal line absent or short and impressed only posteriorly; parascutal carina broad, reaching pronotum. Mesoscutellum ovate, slightly longer than broad; disk of mesoscutellum, rugose, reticulated or dull rugose only laterally and posteriorly, overhanging metanotum, glabrous or with sparse long setae; circumscutellar carina complete. Mesoscutellar foveae transverse, about 2.0× as broad as high, with smooth glabrous bottom, divided by narrow rugose elevated central carina. Mesopleuron entirely covered with delicate interrupted parallel striae, without setae or only setose ventrally ( Figs. 6, 26); mesopleural triangle smooth, with a few strong irregular striae and long white setae; dorsal and lateral axillar areas smooth, glabrous; axillula with delicate parallel longitudinal striae; subaxillular bar smooth, glabrous, triangular, posteriorly as high as height of metanotal trough; metapleural sulcus reaching mesopleuron at mid-height or slightly above, upper part of sulcus also distinct, sulcus separating smooth, glabrous area, with some setae in lower part. Metascutellum smooth, glabrous or coriaceous, as high as height of smooth, glabrous ventral impressed area; metanotal trough smooth, glabrous; central propodeal area smooth, glabrous, with or without delicate rugae in posterolateral part; several parallel indistinct, interrupted, incomplete lateral propodeal carinae bent outwards in mid-height or posterior 1/3 ( Figs. 9, 29); in some cases, lateral carinae absent; lateral propodeal area smooth, with long white setae and piliferous points. Nucha with strong longitudinal sulci dorsally and laterally. Tarsal claws with basal lobe.

Fore wing longer than body, hyaline, with distinct dense cilia on margin, veins dark brown, radial cell open, 3.2–4.5× as long as broad; Rs not reaching wing margin, R1 indistinct, less pigmented, not reaching wing margin; areolet small, triangular, closed and distinct. Rs+M inconspicuous, its projection reaching basalis slightly below or in lower half of its height.

Metasoma as long as, or longer than, head+mesosoma, slightly longer or shorter than high in lateral view; second metasomal tergum extending to half-length of metasoma in dorsal view, with a few white setae anterolaterally, without micropunctures; third and fourth terga smooth, glabrous, without micropunctures; subsequent terga without or with rare delicate micropunctures ( Figs. 11, 30, 55). Hypopygium with or without micropunctures, prominent part of ventral spine of hypopygium 2.3–5.1× as long as broad in ventral view, with a few white setae ventrally. Body length 1.5–2.5 mm.

Sexual generation females and males are known for D. ignotum and D. quercuslanigerum . Sexual females differ from asexual females by the mesoscutellum not overhanging the metanotum; males are distinct in having antennae with 14 flagellomeres all with placodeal sensilla, F1 curved, and the first metasomal tergum in the form of a long petiole (see also the description of the sexual generation of D. ignotum below).

Fifteen species belong to Druon and can be distinguished by the following key.

Key to asexual generation females of Druon species

1. Head completely dark brown to black in frontal and posterior view ( Figs. 1, 15, 46), without light marks; notaulus incomplete or complete, weakly impressed anteriorly ( Figs. 7, 18, 52); mesosoma dark brown to black; coxae and femora dark brown to black at least in proximal half, rest of the leg amber ( Figs. 5, 14, 16–17).......................................... 2

- Head rusty brown, light brown or yellowish, at least in frontal view ( Figs. 20, 69, 101); mesosoma usually light brown to yellowish-brown ( Figs. 25, 74, 105); if colour different, then notaulus strongly impressed on its entire length; legs uniformly reddish brown or amber ( Fig. 136)........................................................................ 6

2. Height of eye 2.5× longer than malar space. Fore wing with pale, almost inconspicuous veins. Prominent part of ventral spine of hypopygium 2.0× longer than broad................................................ garciamartinonae sp. nov.

- Height of eye 3.3x longer than malar space or longer. Fore wing with dark brown veins. Prominent part of ventral spine of hypopygium at least 3.5× longer than broad................................................................ 3

3. OOL subequal or shorter than diameter of lateral ocellus ( Fig. 47); mesoscutum shorter than broad ( Fig. 52); prominent part of ventral spine of hypopygium 3.5× as long as broad.......................................... gregori , sp. nov. (part)

- OOL longer than diameter of lateral ocellus ( Fig. 2); mesoscutum at least as long as broad ( Fig. 7); prominent part of ventral spine of hypopygium 4.5–5.0× as long as broad............................................................. 4

4. Head transversally ovate in frontal view; transfacial distance longer that eye height; torulus slightly above mid height of face ( Fig. 222); clypeus same color as lower face; notaulus complete, weakly impressed anteriorly, with notaulus furrow smooth ( Figs. 227, 229).......................................................................... serretae , sp. nov.

- Head trapezoid in frontal view; transfacial distance subequal or shorter than eye height; torulus at mid height or in lower part of face ( Figs. 1, 16); clypeus paler than lower face; notaulus incomplete ( Figs. 7, 18), not impressed anteriorly or, if complete, then notaulus furrow completely alutaceous................................................................ 5

5. Transfacial distance as long as the height of eye; torulus below the mid height of face ( Fig. 1); notaulus complete, notaulus furrow alutaceous ( Fig. 7); lateral propodeal carinae weak, fragmented, incomplete ( Fig. 9)............ alexandri , sp. nov.

- Transfacial distance shorter than height of eye; torulus at mid height of face ( Figs. 15–16); notaulus furrow smooth ( Figs. 18–19); lateral propodeal carinae complete, never fragmented ( Fig. 19)...................... flocculentum , comb. nov.

6. Head rusty brown frontally, dark brown to black posteriorly ( Figs. 20–23, 69–72); mesosoma dark brown to black, uniformly colored ( Figs. 25–27, 74–76)............................................................................ 7

- Head rusty brown frontally and posteriorly ( Figs. 101–103); mesosoma paler, usually bicolored or light brown to yellowishbrown ( Figs. 118–121, 157–158)......................................................................... 9

7. Gena strongly broadened behind eye in frontal view ( Fig. 69); mesosoma dark brown; mesoscutellar fovea finely rugose, not delimited ventrally from disc of mesoscutellum, gradually continuing into disc, not separated by central carina ( Fig. 77), mesoscutellar disc finely rugose; prominent part of ventral spine of hypopygium slightly longer than broad in ventral view ( Fig. 79)................................................................................. ignotum , comb. nov.

- Gena not or slightly broadened behind eye in frontal view ( Fig. 20); mesosoma dark brown to black; mesoscutellar fovea smooth, glabrous, well delimited from disc of mesoscutellum, separated by central carina ( Fig. 28), mesoscutellar disc coriaceous; prominent part of ventral spine of hypopygium 3.5–4.0× as long as broad in ventral view ( Fig. 30)............... 8

8. Inner margins of eyes converging ventrally; notauli complete and well-delimited, impressed along all their length; mesoscutellar foveae divided by a strong carina..................................................... fullawayi , comb. nov.

- Inner margins of eyes parallel; notauli incomplete, indistinct from sculpture on anterior half; mesoscutellar foveae divided by an alutaceous elevated triangle......................................................... gregori sp. nov. (part)

9. Third tergum reticulate, subsequent terga with micropunctures ( Fig. 110–111).................................... 10

- Third and subsequent terga smooth or with micropunctures ( Fig. 123)........................................... 11

10. Pale yellow specimens; head transversally ovate ( Fig. 101); flagellomeres of similar thickness ( Fig. 104); sides of mesoscutum only slightly darker ( Fig. 107); second metasomal tergum smooth or sometimes reticulated in the posterior part ( Fig. 111)................................................................................ linaria , stat. rev., comb. rev.

- Brown specimens; head trapezoid ( Fig. 177); with the distal flagellomeres thicker than rest of antenna ( Fig. 181); sides of mesoscutum conspicuously darker ( Fig. 184); second metasomal tergum usually with weak striae distally or dorso-apically, rarely smooth ( Figs. 188–189)......................................... quercuslanigerum comb. nov. var. striatum n. var.

11. Notaulus incomplete, extending to 1/2–2/3 of mesoscutum length ( Fig. 132); mesoscutellar foveae in a form of transverse semilunar impression, without central carina or carina incomplete and weakly elevated, foveae always fused ( Fig. 133)....................................................................................... protagion , comb. rev.

- Notaulus complete or extending at least 4/5 length of mesoscutum ( Fig. 120); mesoscutellar foveae transverse, divided by narrow rugose elevated triangular central carina ( Fig. 121)...................................................... 12

12. Short median mesoscutal line present ( Figs. 146, 158); central area of mesoscutellar disk glabrous and coarsely reticulated ( Figs. 147, 159)...................................................................................... 13

- Median mesoscutal line, inconspicuous or in a form of impressed central narrow stripe ( Figs. 171, 217); mesoscutellar disc uniformly pubescent and rugate ( Figs. 121, 195)............................................................ 14

13. Body brown, head transverse, gena distinctly broadened through entire lateral margin of eye in frontal view; mesoscutellum 1.2× as long as broad, with subparallel sides ( Fig. 147); speculum uniformly striate ( Fig. 145).... quercusflocci , comb. nov.

- Body yellow, head trapezoid, gena only slightly broadened behind eye in frontal view, broader in lower half of eye; mesoscutellum rounded or slightly elongated ( Fig. 159); speculum smooth ( Fig. 157)................................................................................................... quercuslanigerum , comb nov. var. quercuslanigerum

14. Ocelli elevated in frontal view ( Fig. 164); last flagellomeres broader distally ( Fig. 168); prominent part of ventral spine of hypopygium 2.0× as long as broad in ventral view.......................................................... 15

- Ocelli not elevated in frontal view; last flagellomeres not or only slightly broader distally ( Figs. 190, 199); prominent part of ventral spine of hypopygium at least 2.5× as long as broad in ventral view....................................... 16

15. Head trapezoid ( Fig. 164); eye black; genae laterally broadened behind the eyes; fore wing venation dark brown ( Fig. 174)............................................................ D. quercuslanigerum comb. nov. var. fuscum n. var.

- Head transversally ovate; eye grey; genae not broadened behind the eyes ( Fig. 57); fore wing venation pale brown, sometimes inconspicuous ( Fig. 66)................................................................... hansoni , sp. nov.

16. Head trapezoid, transverse in frontal view ( Fig. 113); LOL 1.4× as long as diameter of lateral ocellus ( Fig. 114); mesoscutum, pronotum laterally, mesopleuron with long, numerous setae ( Figs. 118–121); speculum sculptured ( Fig. 119); metasoma with dense micropunctures ( Fig. 123).......................................................... pattoni , comb. nov.

- ead rounded in frontal view ( Fig. 190); LOL equal or slightly longer than diameter of ocellus ( Fig. 191); mesoscutum, pronotum laterally, mesopleuron glabrous, with scarce pubescence; speculum smooth or weakly carinate ( Fig. 194); metasoma without micropunctures ( Fig. 198)............................................................................. 17

17. Mesoscutum uniformly reddish-brown; Rs vein curved, radial cell of fore wing less than 3.5× as long as broad prominent part of ventral spine of hypopygium 3.5× as long as broad in ventral view ( Fig. 220).................... rusticum , comb. rev.

- Mesoscutum black, with variable paler area around notaulus in posterior end and sometimes extending to the total length of the notauli; Rs vein straight, radial cell of fore wing 4.5× as long as broad prominent part of ventral spine of hypopygium 4.5× as long as broad in ventral view ( Fig. 198).................................................... receptum , comb. rev.

Below we provide descriptions of new species and redescriptions of species transferred from Andricus , according to current morphological criteria and terminology. Descriptions of galls, data on biology and distribution are also provided.