Disholcaspis mamillana Weld, 1957

Cooke-Mcewen, Crystal & Gates, Michael, 2020, Contributions to Disholcaspis Dalla Torre And Kieffer (Hymenoptera: Cynipidae: Cynipini), Zootaxa 4859 (3), pp. 355-382 : 365-368

Disholcaspis mamillana Weld, 1957 , sexual generation

Material examined: Specimens with USNM barcode labels USNMENT00961866 (♀), USNMENT00961522 (♀), USNMENT00961943 (♀), and USNMENT00961819 (♀) from the earlier molecular analysis .

Diagnosis: This sexual generation is diagnosed by the following combination of traits unique to this Disholcaspis sexual generation compared to all others currently known: body dark brown, F2 0.75–0.9x shorter than F1, wing veins dark brown, extended portion of ventral hypopygial spine tapering evenly to tip, and extended portion of ventral hypopygial spine 1.7–2.2x as long as broad basally. Found on Q. douglasii .

Sexual female ( Fig. 11–19 ): Total body length 2.1–2.5mm. Color. Antennae and mouth palps brown, sometimes F1–4 slightly lighter brown; head, mesosoma, and coxae dark brown to black; legs light brown to golden; metasoma dark brown; wings hyaline with dark brown veins.

Head ( Fig. 12–14 ). Anteriorly 1.3x as broad as high, finely coriaceous with malar space more delicately coriaceous; rounded in anterior view with ocelli raised; lower face with sparse setae. Gena not broadened behind compound eye in anterior view; lateral width of the gena 0.34x as wide as the compound eye height. Compound eye 0.7x as high as frontal head height, transfacial line 0.9x as long as compound eye height; length of malar space 0.2x height of compound eye; compound eyes parallel. LOL 0.82–1x as long as the lateral ocellus; OOL 0.86x length of lateral ocellus; POL 2.3–2.6x as long as OOL and 2–2.4x as long as length of lateral ocellus. Diameter of torulus subequal to distance between them; distance between torulus and compound eye margin subequal to the diameter of torulus. Clypeus rectangular, 0.9x as broad as high, ventral margin convex; tentorial pits present; clypeo-pleurostomal line indistinct; epistomal sulcus broad, shallow, smooth, and bare. Occiput rounded and without carina. Labial palpus 3-segmented, maxillary palpus 4-segmented. Antennae 14–segmented; pedicel 1.3x as long as broad; antennal segment length ratio 19:11:30:22:22:21:18:16:13:12:11:12:11:16; placoid sensilla present on F3–12.

Mesosoma ( Fig. 15–18 ). Laterally 1.1x as long as high. Pronotum setose medially, setose dorsally, ventrally with sparse setae, margin along mesopleuron with fine striations; impressed along propleuron. Propleuron striate along margins, flat medially. Mesoscutum delicately coriaceous lateral to the notauli and along anterior margin, sometimes very delicately coriaceous between notauli; 1.1x as wide as long. Notauli present in posterior 2/3 fading to coriaceous texture anteriorly, incomplete and converging posteriorly; anterior parallel lines not visible; parapsidal lines broad and smooth, extending just over 1/3 length of mesoscutum; median mesoscutal line absent; setae along notauli and lateral margin of mesoscutum. Mesoscutellum slightly longer than broad, rugose, overhanging metanotum; scutellar foveae indistinct sometimes smooth and sometimes with rugose texture intruding. Mesopleuron mostly smooth with several indistinct transverse striations, with sparse setae in the striated area and near mesocoxa foramen; mesopleural triangle setose and with transverse striations; acetabular carina distinct. Dorsoaxillar area smooth but setose, slightly convex; axillar carina with longitudinal striae; axillula setose and smooth; subaxillular bar smooth; metapleural sulcus reaching mesopleuron just over half its height. Metascutellum delicately rugose; metanotal trough smooth and with setae; ventral impressed rim smooth. Lateral propodeal carinae bent outward at the middle sometimes nearly merging dorsally forming a ring, medial propodeal area with medial carina extending over half way to the nucha; lateral propodeal area setose; nucha short with longitudinal carinae. Forewing extending beyond apex of metasoma; radial cell 3.8x as long as wide; Rs curved slightly, nearly reaching wing margin; areolet closed and indistinct; Rs+M reaching or nearly reaching M. Tarsal claws with basal lobe.

Metasoma. Tergum 2 with setae laterally, following 4 terga without setae; all terga smooth and shiny. Ventral hypopygial spine ( Fig. 19 ) tapering evenly to tip, extended portion 1.7–2.2x as long as broad basally, with subapical setae reaching beyond spine apex.

Male: Unknown.

Gall (Fig. 20): Length 2.4–2.9mm, buff-colored, oblong grain-shaped, bluntly pointed, thin walled, and glabrous. Arising from the buds at the base of new leaves during spring flush. Emergence holes are rough edged and near the apex.

Host plant remarks: The recorded host for the asexual generation wasps is Q. douglasii ( Weld 1957) . All sexual generation specimens here identified as D. mamillana were taken from a field identified Q. douglasii . No host voucher is available for these specimens.

Figures

FIGURES 11–16. 11–13 Sexual female Disholcaspis mamillana, (11) lateral habitus; (12) antenna; (13) anterior head; (14) dorsal head; (15) lateral mesosoma, (16) dorsal mesosoma.

FIGURES 17–19. Sexual female Disholcaspis mamillana, (17) propodeum; (18) wing; (19) ventral hypopygial spine; (20) sexual generation gall.