The Wharton Lab

Protarchus Foerster, 1869: 201. Type species: Tryphon rufus Gravenhorst, 1829 [ = Ichneumon testatorius Thunberg, 1822]. Subsequent inclusion by Woldstedt (1877: 441). Monobasic.

Zacalles Foerster, 1869: 204. Type species: Zacalles magnus Davis, 1897. Subsequent inclusion by Davis (1897: 283). Monobasic. Synonymized by Cushman (1924: 8).

Protarchoides Cushman (1922: 25). Type species: Protarchoides longipes Cushman, 1922. Original designation. Synonymized by Townes (1945: 505).

Protarchus is Holarctic in distribution with known hosts confined to the Cimbicidae. The following valid species were included by Yu et al. (2012):

Protarchus antiquus Statz, 1936
Protarchus atrofacies Leblanc, 1999
Protarchus bolbogaster Leblanc, 1999
Protarchus grandis (Thomson, 1888)
Protarchus heros (Holmgren, 1857)
Protarchus magnus (Davis, 1897)
Protarchus melanurus (Thomson, 1894)
Protarchus mellipes (Provancher, 1886)
Protarchus pallidicornis (Walley,1938)
Protarchus sorbi (Ratzeburg, 1844)
Protarchus testatorius (Thunberg, 1822)

The Nearctic species were revised by Leblanc (1999), and this revision includes two species with Holarctic distribution.

Typical members of the genus Protarchus are easy to recognize by their large body size, sharply impressed notauli, relatively short hind wing CU1, and broad, U-shaped groove between the anterior end of the lateral longitudinal carina and the posterior margin of the metathorax. Some individuals, such as the one shown in Fig. 5, also have a well-developed ramulus (apparently lacking in other mesoleiines) though in about half the specimens examined, the ramulus was represented only by a short, barely detectable spur. The short, broad mandibles and narrow clypeus are similar to those in Himerta and Perispuda.

There is at least one species that does not have sharply impressed notauli and it also has a relatively longer CU1. This species could run to Lamachus in the key to genera of Mesoleiini by Townes (1970). However, the deep U-shaped groove and more heavily sculptured propodeum are sufficiently distinct to identify it as Protarchus.

Clypeus (Fig. 2) tall, narrow, usually bulging with rounded transverse ridge dorsally, flattened to weakly impressed ventrally, rarely completely falttened; ventral margin sharp throughout, truncate to narrowly concave medially, with lateral margins distinctly angled dorsally; epistomal sulcus usually shallow, not sharp. Malar space about 0.4-0.6 times basal width of mandible. Mandible (Fig. 2) short, strongly curved, very broad basally, somewhat abruptly narrowing from base to middle, then more nearly parallel-sided over apical half; dorsal tooth varying from about equal in length to ventral tooth to slightly longer, dorsal tooth usually broader than ventral tooth; ventral margin carinate, usually strongly so. Inner eye margins parallel. Female ocelli often small, with maximum diameter of lateral ocellus distinctly shorter than distance between ocellus and eye, ocellus slightly larger in some specimens examined, with diameter more nearly equal to distance from ocellus to eye. Antennae often a little shorter than body; relative lengths of first two flagellomeres as in Fig. 1. Hypostomal carina joining occipital carina well above base of mandible; occipital carina complete. Epomia usually (80%) absent. Dorsal end of epicnemial carina weak, not extending to anterior margin of mesopleuron; mesopleuron punctate, usually coarsely so, occasionally with punctures confluent to form weakly rugulose sculpture, otherwise polished, not mat. Notaulus usually exceptionally well developed (Fig. 3), deeply and narrowly impressed on anterior declivity, the deep incision extending anteriorly to margin and posteriorly usually to level of anterior margin of tegula, either absent posteriorad tegula or weaker, the two sides converging to a shallow median depression. Deep, broad, U-shaped groove visible in lateral view between anterior end of lateral longitudinal carina and thorn-like extension of posterior margin of metathorax. Pleural carina usually distinct dorsoanteriorly, weak to absent ventroposteriorly; propodeal carinae rarely weakly developed and nearly absent; usually (Fig. 4) in form of rounded ridges: lateral longitudinal carina usually complete, median longitudinal carinae narrowly separated medially; posterior transverse carina often complete, with petiolar area roughly delimited; propodeum coarsely sculptured. Legs with apical comb on posterior side of hind tibia short but often well developed, moderately dense; hind tibial spurs long, slender (Fig. 1), longest spur nearly as long as half length of long hind leg basitarsus; all tarsal claws simple, not pectinate. Fore wing (Figs 1, 5) with areolet present; stigma very narrow, not discrete distally, Rs+2r arising from basal 0.3-0.4; remnant of RS+M (the ramulus of Townes 1970) often present and sometimes long as in Fig. 5. Hind wing with first abscissa of CU1 usually much longer than 1cu-a, sometimes nearly equal in length. T1 (Fig. 6) not long and narrow, gradually widening posteriorly; dorsal carinae represented by tall ridges basally delineating margins of deep basal depression of dorsal tendon attachment, more rounded posteriorly, nearly always extending to level of spiracle, sometimes extending nearly to apical margin as low, rounded elevations; dorsal-lateral carina sharp and distinct from spiracle to posterior margin of T1; glymma deep, broad basally, narrowing posteriorly. S1 not extending to level of spiracle, about 0.3-0.4 times length of T1. T2 thyridium present; laterotergites of T2 and T3 completely separated by creases. Ovipositor short, more or less straight, with deep, broad subapical, dorsal notch; ovipositor sheath (Fig. 1) about as long as posterior hind tibial spur. Apex of female metasoma as in Fig. 1.

The species of Protarchus are large and relatively stout.

This description is modified from Townes (1970) and based largely on about five Palaearctic species in the Texas A&M University Collection.

This page was assembled by Bob Wharton as part of a larger collaborative effort on the genera of Ctenopelmatinae. Page last updated May, 2015.

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 are also grateful to 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. We also thank David Wahl for useful feedback throughout our study. 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, Caitlin Nessner, Mika Cameron, Karl Roeder, Danielle Restuccia, and Cheryl Hyde graciously assisted us 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 nos DEB 0723663, 0923134, and 1026618.

This material is based upon work at Texas A&M University 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.