Atrusca aequalis ( Kinsey, 1936 )

Atrusca aequalis ( Kinsey, 1936)

Figs 1–14 View FIGURES 1–6 View FIGURES 7–10 View FIGURES 11–14

Cynips View in CoL ( bulboides ) aequalis Kinsey, 1936: 151 , female, gall.

Atrusca aequalis (Kinsey) : Weld 1952: 313.

Types examined. HOLOTYPE female Cynips aequalis ( bulboides ) “ Inde 20E Dgo 6300’, Mex. Gall 11.1.31, 70 fms. 2.8.32”, “Q. chihuahuens, Kinsey coll.”, red “ Cynips aequalis , Holo- Paratype ”, deposited in AMNH, NYC, examined by GM. Five PARATYPE females “ Inde 20E, Dgo 6300’, Mex., galls 11.1.31. 70 females 2.8.32”, “ Quercus chihuahuensis, Kinsey View in CoL coll.”, red label “ Cynips View in CoL equalis. Paratype ”, deposited in the general collection in AMNH, NYC, examined by GM.

Diagnosis. Atrusca aequalis belongs to the couplet characterized by exhibiting brachypterous or normal length fore wings, with a complete and conspicuous venation, the Rs vein of radial cell being strongly curved distally, never almost straight, the entirely rugose mesoscutellum, the mesoscutellum with a posterocentral invagination, and a very long ventral spine of the hypopygium (10.0–10.5× as long as broad) with few short setae ventrally which do not extend beyond apex of the spine, as in A. cucurbita . Atrusca aequalis can be distinguished from A. cucurbita by the quadrangular head in frontal view; the interocellar area not elevated in frontal view but the lateral ocelli are prominent; the notauli maintain the same width along their entire length; and the mesoscutum is alutaceous-reticualte, while in A. cucurbita the head is ovate in frontal view; the interocellar area is elevated above the head; the notauli are wider posteriorly, and the mesoscutum is uniformly rugose.

Re-description. Asexual female ( Figs 1–13 View FIGURES 1–6 View FIGURES 7–10 View FIGURES 11–14 ). Head, antenna, palpi dark reddish brown, central part of lower face and area between toruli black; propleuron light brown, mesoscutum reddish brown with black stripes along parapsidal lines and in between notauli in anterior 1/2–2/3; legs dark brown to black; second metasomal tergum dark reddish brown, black in posterior 1/3, third tergum black, subsequent terga and hypopygium reddish brown.

Head quadrangular in frontal view, alutaceous, with sparse white setae, 1.2× as broad as high and as broad as mesosoma in frontal view, 1.8× as broad as long in dorsal view. Gena alutaceous, not broadened behind eye in frontal view, narrower than transverse diameter of eye in lateral view. Malar space alutaceous, with delicate inconspicuous striae radiating from clypeus; malar sulcus absent; eye 2.4× as high as height of malar space. Inner margins of eyes parallel or slightly diverging ventrally. POL 2.0× as long as OOL; OOL 1.5× as long as diameter of lateral ocellus and 1.2× LOL; all ocelli ovate, central ocellus larger. Transfacial distance 1.2× as long as height of eye and 1.4× as long as height of lower face; diameter of antennal torulus 1.4× as long as distance between them, distance between torulus and eye equal to diameter of torulus; lower face alutaceous along eyes, dull rugose centrally, under toruli, with few setae; slightly elevated median area rugose, shining, without setae. Interocellar area not elevated above head in frontal view, lateral ocelli prominent. Clypeus impressed, uniformly coriaceous to rugose, rectangular, broader than high, with few long setae; ventrally rounded, emarginate, without median incision; anterior tentorial pit large, rounded, epistomal sulcus and clypeo-pleurostomal line broad, well impressed. Frons and interocellar area rugose, without striae, with short setae. Small rounded impressed area below central ocellus smooth, shining. Vertex, occiput, postgena alutaceous-reticulate, with sparse white setae, postocciput smooth, shining; posterior tentorial pit large, ovate, area below impressed; occipital foramen slightly higher than height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulci which run parallel ventrally, bent outwards towards occipital foramen, postgenal bridge dorsally broader than width of occipital foramen. Antenna slightly shorter than body, with 12 flagellomeres, pedicel as long as broad, F1 1.3× as long as scape+pedicel and 1.1× as long as F2; F2 1.1× as long as F3; F3 1.4× as long as F4, F5=F6, F7=F8, F9 till F11 shorter, nearly equal in length, F12 1.5× as long as F11; placodeal sensilla on F2–F12.

Mesosoma 1.2× as long as high, with short white setae. Pronotum rugose, with net of irregular rugae laterally, shining; propleuron along sides alutaceous, smooth, shining centrally. Mesoscutum uniformly alutaceous-reticulate, with piliferous points and dense setae anteriorly; slightly longer than broad (greatest width measured across mesoscutum at level of base of tegulae). Notaulus complete, with the same width along its entire length with the same width along its entire length, deep, broad, with smooth, glabrous bottom, posteriorly broader and slightly converging; anterior parallel line indistinct, extending to 2/3 of mescutum length; parapsidal line, hardly traceable, indicated by smooth black stripes; median mesoscutal line absent; parascutal carina narrow, smooth, reaching notaulus. Mesoscutellum uniformly dull rugose, trapezoid, broader in posterior 1/3, posteriorly rounded, with invagination posterocentrally; overhanging metanotum; mesoscutellar foveae with smooth, shining bottom, without rugae, transverse, broader than high, separated by narrow elevated rugose central carina. Circumscutellar carina complete. Mesopleuron delicately alutaceous in anterior half, smooth, shining in posterior half, with few scattered setae, speculum smooth, shining; mesopleural triangle smooth, shining, without striae, with dense setae; dorsal and lateral axillar areas smooth, shining, with dense setae; subaxillular bar smooth, shining, most posterior part slightly shorter than height of metanotal trough; metapleural sulcus reaching mesopleuron at mid height, upper part of sulcus only partially distinct. Metascutellum delicately coriaceous, slightly shorter than height of smooth, shining ventral impressed area; metanotal trough smooth, shining, with sparse setae; central propodeal area smooth, shining, with some longitudinal rugae posteriorly; lateral propodeal carinae bent outwards in posterior 1/3; lateral propodeal area coriaceous-rugose, shining, with long dense white setae. Nucha with irregular rugae laterally and dorsally. Tarsal claws toothed, with basal lobe.

Fore wing longer than body, uniformly infuscated, margin with long dense cilia, with few darker spots and stripes, veins dark brown, radial cell open, 2.0× as long as broad; second abscissa of Rs strongly curved distally; R1 and Rs nearly reaching wing margin; areolet triangular, Rs+M inconspicuous, traceable along entire length, reaching basalis in lower half of its height.

Metasoma slightly longer than head+mesosoma, higher than long in lateral view; second metasomal tergum extending over half the length of metasoma in dorsal view, with dense white setae anterolaterally, without band of micropunctures posteriorly; subsequent terga with delicate micropunctures. Hypopygium without micropunctures, prominent part of ventral spine of hypopygium 10.5× as long as broad in ventral view, with a few short setae ventrally which do not extend beyond apex of spine.

Body length 2.2–4.0 mm ( Kinsey 1936).

Gall ( Fig. 14 View FIGURES 11–14 ). The gall is similar to all galls of Kinsey’s bella and dugesi complexes. The spherical gall indistinguishable from A. pomifera and A. aspera . Mature galls light straw yellow, somites touched with rose or brown, always conspicuously mottled with purplish brown, up to 15 mm, in average near 10 mm in diameter.

Biology. The asexual generation is only known to induce leaf galls on Q. chihuahuensis , Q. undata . Galls mature in late autumn; adults emerge in January–February next year.

Distribution. Mexico: Chihuahua.