The Wharton Lab

Phaestus Foerster, 1869: 212. Type species: Rhaestus heterocerus Thomson, 1894 (a junior subjective synonym of Grypocentrus anomalus Brischke, 1871), based on subsequent inclusion by Thomson (1894: 2017).

According to Perkins (1962), the synonymy of heterocerus and anomalus should be attributed to Teunisson (1948). Thomson’s paper is listed as published in either 1893 or 1894 by various authors since the generic revision of Pionini by Townes (1970).

The following valid species were included in Yu et al. (2012), even though Townes (1970) indicated that there was only a single species known.

Phaestus anomalus (Brischke, 1871)
Phaestus nigriventris Roman, 1937

As indicated by Townes (1970), Phaestus is unusual in that the first flagellomere is shorter than the second. Townes (1970) mentions that only Cacomisthus, a Neotropical genus, shares this feature among the genera he included in Pionini. The ventral margin of the clypeus is largely obscured by a dense covering of setae in the type species, the face is very short, with the malar space absent, at least in the female, and there is a deeply impressed sternaulus anteriorly.

Female with inner eye margins converging ventrally (Fig. 2). Clypeus uniformly setose dorsally, densely setose along ventral margin as in some tryphonines (Fig. 2); ventral margin weakly, evenly convex; epistomal sulcus distinctly impressed throughout; clypeus convex in profile. Face densely but relatively finely grandular punctate, protruding medially; frons longer than face; frons and vertex finely punctate, nearly smooth. Malar space absent. Mandible (Figs 3, 4) without basal transverse depression; ventral margin sharp, not rounded; ventral tooth distinctly longer than dorsal tooth; with sharp diagonal ridge across outer surface from dosal condyle to base of ventral tooth. Maxillary palp very short, only about half height of head; antenna shorter than body in female (Fig. 1); first flagellomere shorter than both scape and second flagellomere (Figs 3, 4). Occipital carina complete. Epicnemial carina almost reaching anterior margin of mesopleuron. Notaulus very short but distinct at base, extending onto anterior portion of disc as a broad, very weak impression, not extending posteriorly to level of tegula. Sternaulus a deep, sculptured impression narrowing posteriorly, covering anterior half of mesopleuron. Groove between propodeum and metapleuron broadly u-shaped, readily visible in lateral view; broad, u-shaped groove mid-dorsally between propodeum and metanotum present; pleural carina well-developed, complete; median and lateral longitudinal carinae well developed as are anterior and posterior transverse carinae (Fig. 5); areola large and distinct. Hind femur somewhat thickened (Fig. 1); apical margin of mid tibia expanded into a tooth weaker than but similar to that of fore leg; apical comb on posterior side of hind tibia absent; posterior hind tibial spur more than 7x longer than maximum width at base, hind tibial spurs unequal in length; tarsal claws small, difficult to see, not pectinate according to Townes (1970). Fore wing with areolet absent; stigma short and broad, with Rs+2r arising near midpoint of stigma. Hind wing (Fig. 1) with first abscissa of CU1 slightly longer than 1cu-a. T1 (Fig 7-9) strongly and somewhat evenly broadening from base to apex; dorsal carinae well-developed to a little posteriorad level of spiracle, absent over posterior 0.2-0.3; dorsal-lateral carina complete between spiracle and apex of T1; glymma (Fig. 8) shallow. S1 not extending to level of spiracle, shorter than half length of T1. T2 thyridium absent (Fig. 9). Ovipositor and sheath straight (Fig. 11).

This description is expanded from that given by Townes (1970), who also included Phaestus in a key to genera of Pionini.

Brischke (1871) recorded the type species from Fenusa larvae mining leaves of oaks (Quercus) Townes (1970).

This page was assembled by Bob Wharton as part of a larger collaborative effort on the genera of Ctenopelmatinae.

This work would not have been possible without the groundwork provided by Ian Gauld’s study of the Australian and Costa Rican faunas, and we are particularly grateful for his assistance in many aspects of this study. We also thank David Wahl of the American Entomological Institute and Andy Bennett of the Canadian National Collection for extended loans of the material used for this study and particularly Dave Karlsson for sending valuable material from the Swedish Malaise Trap Survey. Matt Yoder provided considerable assistance with databasing issues, and our use of PURLs (http://purl.oclc.org) in this regard follows the example of their use in publications by Norm Johnson. Heather Cummins, Andrea Walker, Patricia Turner, Caitlin Nessner, Amanda Ladigo, and Cheryl Hyde graciously assisted with image processing, formatting, and literature retrieval. This study was supported by the National Science Foundation’s PEET program under Grant No. DEB 0328922 and associated REU supplement #s DEB 0723663, 0923134, and 1026618. Page last updated Jan, 2015.

This material is based upon work supported by the National Science Foundation under Grant Number DEB 0328922 with REU supplements DEB 0723663, 0923134, and 1026618. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.