Druon rusticum 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 : 68-72

Druon rusticum Kinsey, 1937 , comb. rev.

Figs. 210–221

Druon rusticum Kinsey, 1937: 64 , female, gall.

Andricus rusticum (Kinsey) : Weld, 1952a.

Types examined. Female holotype “Taxco 8NE Gro 8000’, Mex. Gall 1.7.32., 66 fms. 4.15.32.”, “ Q. macrophylla, Kinsey coll.”, red “ Druon rusticum , Holo- Paratype”. Holotype deposited at the AMNH, NYC, examined by GM.

Additional material examined. Ten paratypes with the same labels as the holotype, deposited in AMNH, NYC, examined by GM .

Diagnosis. This species belongs to the Druon species group with the head rounded and rusty brown frontally, LOL equal or slightly longer than diameter of ocellus, mesosoma light brown with notaulus complete or extending at least 4/5 length of mesoscutum, mesoscutal foveae present separated by a triangular central area and metasoma smooth or with indistinct sparse micropunctures. The most similar species is D. receptum , but they differ in the mesoscutum being uniformly reddish–brown with a central narrow longitudinally impressed stripe extending to half the mesonotum length in D. rusticum ( Fig. 217 ) (with black areas and lacking the stripe in D. receptum ( Fig. 195 )); in the speculum being smooth in D. rusticum ( Fig. 216 ) (weakly carinated in D. receptum ( Fig. 204 )); and in the prominent part of ventral spine of hypopygium being 4.5× as long as broad in ventral view in D. rusticum (3.5× as long as broad in D. receptum ).

Redescription. Asexual female ( Figs. 210–220 ). Head uniformly light brown; antenna yellowish-brown; mesosoma uniformly chestnut to dark brown; mesoscutum uniformly reddish brown; metasoma brown to blackish brown; legs uniformly yellowish brown.

Head rounded, broadest part above toruli, 1.2× as broad as high and slightly broader than mesosoma in frontal view, with sparse setae, denser on lower face; 2.3× as broad as long in dorsal view. Gena alutaceous, slightly broadened behind eye in frontal view, as broad as transverse diameter of eye in lateral view. Malar space with a few delicate striae radiating from clypeus and reaching eye; eye 2.8× as high as length of malar space. Inner margins of eyes parallel. POL 2.75× as long as OOL, OOL slightly longer than diameter of lateral ocellus and equal LOL, all ocelli ovate, of same size. Transfacial distance slightly shorter than height of eye; toruli located above mid-height of eye, frons shorter than height of lower face, diameter of torulus 1.8× as long as distance between them, distance between torulus and eye as long as diameter of torulus; lower face alutaceous, with sparse white setae; slightly elevated median area alutaceous, glabrous, with few setae; delicate striae radiating from clypeus into lower face, reaching eye margin. Clypeus flat, ovate, only slightly broader than high, smooth, glabrous, with a few long setae along ventral edge; ventrally rounded, not emarginate and without median incision; anterior tentorial pit rounded, distinct, epistomal sulcus distinct, clypeo-pleurostomal line well impressed. Frons uniformly alutaceous to microreticulate, without striae or setae, area between toruli and eye also alutaceous; interocellar area alutaceous. Vertex and occiput alutaceous, with white sparse long setae; postocciput and postgena alutaceous-reticulate, without concentric lines around occipital foramen and postgenal bridge; posterior tentorial pit large, elongate, area below impressed; occipital foramen as high as height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulcus which strongly diverge toward occipital foramen, postgenal bridge V-shaped, anteriorly slightly broader than occipital foramen. Antenna slightly longer than head+mesosoma, with 11 flagellomeres, pedicel 1.5× as long as broad; F1 as long as scape+pedicel and 1.3× as long as F2; F2 slightly longer than F3; F3 slightly longer than F4, F5 slightly longer than F6, F7 to F10 equal in length; F11 1.8× as long as F10; placodeal sensilla on F4–F11.

Mesosoma longer than high, with a few white setae, denser along propleuron and lateral propodeal area. Pronotum smooth, glabrous, with numerous delicate parallel striae laterally; propleuron smooth, glabrous, with delicate waved interrupted transverse parallel striae. Mesoscutum uniformly reticulate, slightly longer than broad (greatest width measured across mesoscutum level with base of tegulae). Notaulus deep, complete, smooth, glabrous, broadest posteriorly, gradually narrowing towards pronotum; posteriorly converging; at posterior end the distance between notauli shorter than distance between notaulus and side of mesoscutum. Anterior parallel line impressed, extending around 1/3 of mesoscutum length, not reaching level of tegula; parapsidal line indistinct, extending to level of tegulae; median mesoscutal line absent but with an impressed longitudinal central narrow stripe; parascutal carina narrow, reaching notaulus. Mesoscutum with impressed longitudinal central narrow stripe, starting from pronotum and extending across all mesoscutal surface. Mesoscutellum rounded, only very slightly longer than broad; disk of mesoscutellum reticulate, with dull rugae laterally and posteriorly, overhanging metanotum, with sparse long setae; circumscutellar carina present. Mesoscutellar foveae delimited all around by strong black elevated carinae, transverse, 2.0× as broad as high, foveae smooth, glabrous, divided by triangular rugose central area. Mesopleuron smooth, glabrous, with longitudinal parallel delicate striae, absent on speculum; mesopleural triangle smooth, glabrous, with white setae and some transverse delicate rugae; dorsal and lateral axillar areas smooth, glabrous, with dense white setae; axillula with delicate parallel longitudinal striae; subaxillular bar smooth, glabrous, triangular, posteriorly as high as height of metanotal trough; metapleural sulcus reaching mesopleuron half of its height; upper part of sulcus indistinct; lower part of sulcus delimiting smooth area with dense long white setae. Metascutellum rugose, higher than height of smooth, glabrous ventral impressed area; metanotal trough smooth, glabrous; lateral propodeal carinae distinct, subparallel, slightly bent at mid-height; central propodeal area smooth, glabrous, with distinct parallel rugae, nearly reaching anterior edge of propodeum; lateral propodeal area smooth, glabrous, with sparse white setae and piliferous points. Nucha with net of strong rugae dorsally and laterally. Tarsal claws with basal lobe.

Fore wing slightly longer than body, hyaline, with short cilia on margin, veins light brown, radial cell open, 3.5× as long as broad; Rs and R1 nearly reaching wing margin; areolet triangular, of moderate size, closed and indistinct. Rs+M light brown, extending to 2/3 of distance between areolet and basalis, its projection reaching basalis at half of its height.

Metasoma slightly longer than head+mesosoma, higher than long, second metasomal tergum reaching halflength of metasoma in dorsal view, with white setae anterolaterally, without micropunctures; all subsequent terga and hypopygium without micropunctures; prominent part of ventral spine of hypopygium 4.0× as long as broad in ventral view. Body length 1.3–2.3 mm (n = 10).

Gall ( Fig. 221 ). Wool covered, cream-coloured white to tan and russet brown galls; the individual hairs short, straight, hardly covering the larval cells and obviously tufted about each individual cell; making continuous but very irregular, narrowly elongate masses up to 25 mm, average 13 mm long. The larval cells only 1.5 mm long, elongate, 4 to 10 in one cluster.

Biology. Only the asexual generation is known, which induces galls on Q. magnoliifolia (= Q. macrophylla ; Section Quercus , Series Leucomexicanae); galls mature in late autumn; adults emerge the following year in April– May (Kinsey 1937).

Distribution. Southwestern Mexico, Guerrero (Kinsey 1937).

Figures

FIGURES 210–215. Druon rusticum, comb. rev., asexual female. 210–213, head: 210, frontal view, 211, dorsal view, part, 212, lateral view, 213, posterior view. 214, antenna. 215, mesosoma and propleura, frontal view.

FIGURES 216–219. Druon rusticum, comb. rev., asexual female. 216, mesosoma, lateral view. 217–218, mesoscutum and mesoscutellum dorsal view. 219, metascutellum and propodeum, posterodorsal view.

FIGURES 220–221. Druon rusticum, comb. rev. 220, metasoma, female, lateral view. 221, galls.

FIGURES 194–196. Druon receptum, comb. rev., asexual female (lighter colour). 194, mesosoma, lateral view. 195, mesoscutum and mesoscutellum, dorsal view. 196, metascutellum and propodeum, posterodorsal view.

FIGURES 203–206. Druon receptum, comb. rev., asexual female (darker colour). 203, mesosoma and propleura, frontal view. 204, mesosoma, lateral view. 205, mesoscutum, dorsal view. 206, mesoscutellum, dorsal view.