Atrusca emergens ( Kinsey, 1936 )

Atrusca emergens ( Kinsey, 1936)

Figs 276–289 View FIGURES 276–281 View FIGURES 282–285 View FIGURES 286–289

Cynips View in CoL ( dugesi ) emergens Kinsey, 1936: 113 , female, gall.

Atrusca emergens (Kinsey) : Weld, 1952: 314

Types examined. HOLOTYPE female Cynips View in CoL ( dugesi ) emergens “Sta Isabel 6E Chi 6000’, Mex. Gall 10.24.31, 7 fms. 2.9.32”, “ Q. undata, Kinsey View in CoL coll.”, red “ Cynips emergens , Holo- Paratype ”, deposited in AMNH, NYC, examined by GM. Five PARATYPE females “Sta. Isabel, 6E, Chi 6000’ Mex., galls 10.24.31, 113 females 1.30.32”, “ Q. undata Kinsey View in CoL coll.”, red label “ Cynips emergens . Paratype ”, deposited in the general collection in AMNH, NYC, examined by GM.

Diagnosis. Atrusca emergens belongs to the couplet characterized by a dark brown to black body color, with conspicuous black stripes on the mesoscutum, with a complete fore wing venation, the Rs vein of radial cell being strongly curved distally, never almost straight, the coriaceous pronotum, without any stria or rugae, the entirely rugose mesoscutellum usually with a posterocentral invagination, the mesopleuron sculptured to some degree, with or without piliferous points, the completely alutaceous speculum, and a ventral spine of the hypopygium setose and relatively short, 2.5–4.5× as long as wide, as in A. pomifera . Atrusca emergens differs from A. pomifera by having a triangular head in frontal view, the mesoscutellar foveae displaying a rugose bottom, the lateral propodeal area having piliferous points, the smooth central propodeal area, and the hyaline radial cell, while in A. pomifera the head is transversally ovate, the mesoscutellar foveae are smooth, the lateral propodeal areas lack piliferous points, the central propodeal area exhibit delicate irregular rugae, and the radial cell of fore wings exhibits a dark spot.

Re-description. Asexual female ( Figs 276–288 View FIGURES 276–281 View FIGURES 282–285 View FIGURES 286–289 ). Head triangular to ovate, dark brown, with darker to black central part of lower face and posteriorly; antenna, palpi reddish brown; mesoscutum reddish brown, with black stripes along anterior parallel and parapsidal lines; mesoscutellum reddish brown; mesosoma laterally reddish brown with darker areas, legs dark brown; metasoma lighter than mesosoma, with dark brown posterior band along 2nd metasomal tergum.

Head more or less triangular in frontal view, alutaceous, with sparse white setae, denser on lower face, 1.3× as broad as high and narrower than mesosoma in frontal view, 2.4× as broad as long in dorsal view. Gena alutaceous, slightly broadened behind eye in frontal view, narrower than transverse diameter of eye in lateral view. Malar space alutaceous-reticulate, without striae radiating from clypeus; malar sulcus absent; eye 2.4× as high as height of malar space. Inner margins of eyes slightly diverging ventrally. POL 1.8× as long as OOL; OOL 2.0× as long as diameter of lateral ocellus and 1.4× as long as LOL; all ocelli ovate, of same size. Transfacial distance 1.3× as long as height of eye and 1.5× as long as height of lower face; diameter of antennal torulus 1.3× as long as distance between them, distance between torulus and eye 1.2× as long as diameter of torulus; lower face alutaceous along inner sides of eye, coriaceous in central part below toruli, with white setae, without striae; slightly elevated median area coriaceous, without setae. Interocellar area not elevated above head in frontal view, lateral ocelli prominent. Clypeus impressed, uniformly delicately coriaceous, 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 delicately rugose, interocellar area alutaceous to delicately coriaceous, without striae, with few short setae. Vertex, occiput delicately coriaceous; postocciput, postgena smooth, shining with sparse white setae; 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 towards occipital foramen, dorsally bent outwards, postgenal bridge smooth, shining, anteriorly broader than posteriorly and slightly broader than width of occipital foramen. Antenna slightly shorter than length of body, with 12 flagellomeres, pedicel 1.6× as long as broad, F1 1.2× as long as scape+pedicel and 1.3× as long as F2; F2 1.4× as long as F3; F3 shorter than F2 and equal F4, F5 shorter than F4, F6=F7, subsequent flagellomeres shorter, nearly equal in length, F12 slightly longer than F11; placodeal sensilla on F4–F12.

Mesosoma 1.2× as long as high, with dense short white setae. Pronotum coriaceous dorsolaterally, rest part smooth, shining with dense long setae; propleuron alutaceous along sides, smooth, shining centrally. Mesoscutum uniformly delicately coriaceous, with piliferous points partially obscured basally and with dense white setae; slightly longer than broad (greatest width measured across mesoscutum at level of base of tegulae). Notaulus complete, deep, broad, with smooth, glabrous bottom, posteriorly broader and slightly converging; anterior parallel slightly impressed and extending to 1/4 of mesoscutum length, marked with black stripes; parapsidal lines indistinct, hardly traceable, indicated by smooth darker stripes; median mesoscutal line absent; parascutal carina narrow, smooth, reaching notaulus. Mesoscutellum uniformly dull rugose, ovate, slightly longer than broad, posteriorly rounded, with indistinct shallow invagination posterocentrally; overhanging metanotum; mesoscutellar foveae, transverse, broader than high, with smooth, shining bottom, with some rugae, separated by broad elevated rugose central area. Circumscutellar carina complete. Mesopleuron alutaceous along sides, smooth shining in central part, with setae; speculum uniformly alutaceous, shining, with few setae; mesopleural triangle smooth, shining, with dense setae; dorsal and lateral axillar areas smooth, shining, with dense setae; subaxillular bar smooth, glabrous, most posterior part as high as height of metanotal trough; metapleural sulcus reaching mesopleuron in upper 1/3 of its height, upper part of sulcus distinct. Metascutellum delicately coriaceous, as high as height of smooth, shining ventral impressed area; metanotal trough smooth, glabrous, with sparse setae; central propodeal area smooth, shining, without rugae, most brodest part slightly below midheight; lateral propodeal carinae faintly and gradually bent outwards; lateral propodeal area smooth, shining, with piliferous points and long dense white setae. Nucha with irregular rugae laterally, smooth, shining dorsocentrally. Tarsal claws toothed, with basal lobe.

Fore wing longer than body, but shorter than the usual length, margin with long dense cilia, with few slightly darker spots and stripes, veins dark brown, radial cell open, 1.8× as long as broad, hyaline; second abscissa of Rs strongly curved distally; R1 and Rs nearly reaching wing margin; areolet triangular, indistinct, Rs+M inconspicuous, traceable along entire length, reaching basalis slightly below half of its height.

Metasoma slightly longer than head+mesosoma, higher than long in lateral view; second metasomal tergum extending to 5/6 of metasoma length in dorsal view, with white setae anterolaterally, without band of micropunctures posteriorly; subsequent terga without delicate micropunctures, without setae. Hypopygium without micropunctures, prominent part of ventral spine of hypopygium 4.5× as long as broad in ventral view, with setae extending beyond apex of spine.

Body length 2.2–3.7 mm ( Kinsey 1936).

Gall ( Fig. 289 View FIGURES 286–289 ). The gall is similar to all galls of Kinsey’s bella and dugesi complexes; indistinguishable from A. bella galls. Mature galls rosy or brownish tan, unspotted, up to 22 mm, in average 18 mm in diameter.

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

Distribution. Mexico: Chihuahua.