Pergaphaga Gauld, 1984

Wharton, Robert, Cammack, Jonathan & Mullins, Patricia, 2010, A revision of the westwoodiine genus Pergaphaga (Hymenoptera, Ichneumonidae, Ctenopelmatinae), ZooKeys 37 (37), pp. 35-68 : 46-48

Pergaphaga Gauld, 1984

Pergaphaga Gauld, 1984: 231 . Type species: Pergaphaga nigra Gauld, 1984 by monotypy and original designation.

Pergaphaga: Gupta 1987: 355 (catalog); Yu and Horstmann 1997: 455 (catalog); Zhaurova and Wharton 2009: 34, 39–41, 62–65, 67, 69–77 (key to genera of Westwoodiini , redescription, figures, relationships).

Megaceria auct. (misidentified, not Megaceria Szépligeti, 1908 ): Townes 1970: 57–58, 224 (key, description, figure); Short 1978: 62–64, 259 (larva).

Diagnosis: Clypeus similar in outline in all species (Figs 17–20), with ventral margin broadly truncate or nearly so medially, sharply angled dorsally near lateral margin. First flagellomere with large tyloid containing numerous (>20) placoid sensilla (Figs 14, 15). Occipital and hypostomal carinae meeting ventrally well before base of mandible (Fig. 25). Mesoscutum densely punctate throughout; notauli deep throughout, including at anterior margin (Fig. 27), V-shaped, converging posteriorly in broad, shallow depression separated from scuto-scutellar groove by a weak elevation; mesopleural depression broad and distinct. Propodeum varying from partially and weakly to extensively and strongly rugose (Figs 33–34), but always with some carination visible. Inner hind tibial spur almost twice length of outer spur. Fore wing 2m-cu with a single bulla. Petiolar tergosternal sulcus located ventrally when viewed in profile. Glymma represented by a shallow dorsal depression anteriorly (Fig. 45). S1 extending more than half distance to spiracle, usually to or nearly to level of spiracle. Metasomal segments 1–2 and more rarely 3 with epipleura bare and membranous when visible, often collapsed and extending outwardly as fleshy protrusions in dried specimens. Female gaster laterally compressed apically from middle of T3. In lateral view, cerci attached ventrad middle of posterior aspect of gaster. All four of the known species have hyaline wings with an infumate spot at the tip of the fore wing.

Pergaphaga can be differentiated from other Ctenopelmatinae by a combination of characters specific to Westwoodiini , including fore wing RS+2 r arising from or near the base of the stigma (Figs 36–40), cerci of females ventrally displaced, and first flagellomere with a large tyloid laterally. The tyloid is in the form of a bare patch of numerous (> 20), irregularly arranged placoid sensilla (Figs 14–15).

As noted by Zhaurova and Wharton (2009), Pergaphaga is perhaps the least readily characterized of the known westwoodiines, and the species most closely resemble those currently placed in Dictyopheltes . The species of Pergaphaga and Dictyopheltes are characterized relative to other westwoodiine genera by the shallow to indistinct glymma (Fig. 45), with the petiole thus resembling that of certain Euryproctini . Gauld (1984), in fact, stated that Pergaphaga and Dictyopheltes lacked a glymma, and he used this feature in his key to the Australian genera of ctenopelmatines. A glymma-like depression is present in nearly all individuals that we examined, but is much different in appearance than the deeper glymma of Westwoodia , Gauldia , and Hypopheltes . It is narrow, shallow, and almost slit-like in some specimens, and never as distinct as it is in these other genera.

The sternite of the petiole is longer in Pergaphaga relative to that in Dictyopheltes . Additionally, the species of Pergaphaga are less heavily sculptured than those of Dictyopheltes , and retain at least some visible carination on the propodeum (Figs 33– 34). The most distinctive feature of the propodeum is the presence of a straight to very weakly arched transverse carina or series of low, transverse ridges extending between the propodeal spiracles that is not found in other westwoodiines, and which is variously developed in the new species described below. The monophyly of Pergaphaga is thus largely supported by the patterns of propodeal carination and wing coloration.

Monophyly of Dictyopheltes is supported primarily by two character states: notauli absent at base and propodeum rugose, without distinct carinae ( Gauld 1984, Zhaurova and Wharton 2009).

Biology. The species of Pergaphaga have been reared from pergine sawflies feeding on Eucalyptus , and specifically from Perga affinis ( Carne 1969) , Pergagrapta bella ( Elliot and Bashford 1995) and Pergagrapta gravenhorstii (Westwood) . The latter record is based solely on label data from the type series of P. leaski . There are collection or rearing records from every month except September and November, but the vast majority are from February through June.

Pergaphaga is known only from southeastern Australia, ranging from South Australia, through Victoria and north about midway through New South Wales. In addition to the specimens recorded below under the species descriptions there are published records of Pergaphaga from Tasmania ( Elliot and Bashford 1995), but we have not seen this material. The specimens of P. nigra labeled as South Australia (BMNH) have no additional data, and we are unable to pinpoint the locality further.

Remarks. Pergaphaga is similar in size and general appearance to species of Megaceria , a more commonly encountered ctenopelmatine in the tribe Euryproctini ( Gauld 1984) . Both are Australian endemics, and the two have been confused in the past, prior to the detailed study of the Australian fauna by Gauld (1984). The species of Megaceria lack the distinct tyloid at the base of the outer side of the first flagellomere. The first flagellomere also tends to be longer in Megaceria , with RS generally arising more distally from the stigma and terminating closer to the wing tip. Additionally, the petiole is more completely tubular in Megaceria , with no obvious sulcus between the fused tergum and sternum, the spiracle is more anteriorly displaced, and there is a broader, more distinct bridge separating the foramen of the petiole from the coxal cavities. The shape of the forewing areolet is distinctive in Megaceria , unlike the various forms seen in Pergaphaga . In Megaceria , ornamentation on the frons varies, as does the development of lateral carinae on the scutellum and there’s an unusual amount of variation in the trough and associated carinae and projections along the margin of the propodeum and metanotum. According to Gauld (1984), there are three described species of Megaceria and at least 10 undescribed species.