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Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of the northeastern Nearctic region
CJAI 05, February 19, 2008
doi: 10.3752/cjai.2008.05

Matthias Buck, Stephen A. Marshall, and David K.B. Cheung

Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1

 

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34. Euodynerus schwarzi (Krombein, 1962)
Figs B5.7, 9, 41, 46; C34.1–4.

Euodynerus schwarzi Euodynerus schwarzi Euodynerus schwarzi
Euodynerus schwarzi Euodynerus pratensis Euodynerus schwarzi

Species recognition. Euodynerus schwarzi is very similar to E. megaera, from which it can be separated by the characters given in the key. The differences between the two species are discussed under E. megaera.

Variation. Fore wing length 8–9.5 mm (♂♂), 9.5–12.0 mm (♀♀). The hind margin of tergum 2 varies from being slightly thicker than that of tergum 3 to considerably thickened, especially in the male (thickness of hind margin up to 0.7x mid ocellar diameter). Female clypeus with an arched ivory dorsal spot; male clypeus ivory, usually with narrow black or brownish apical margin, often dilated to form a small black mark between apical teeth. Female scape obscure reddish white below (at least in distal half), rarely in part clear ivory. Mesopleuron with small to large ivory dorsal spot, usually smaller in male than in female. Tegula mainly black, usually with ivory spots anteriorly and/or posteriorly. Parategula with or without ivory mark, sometimes suffused with reddish or completely black. Scutellum sometimes with a pair of small ivory spots. Terga 1 and 2 with apical fasciae; in male terga 3 and 4 often with posterolateral spots, tergum 5 rarely with apicomedial spot. Apical fascia of tergum 1 with more or less straight anterior margin, sometimes with moderate forward extension at extreme sides. Sternum 2 with a pair of ivory spots in posterolateral corners; in male sternum 3 and sometimes 4 and 5 with posterolateral spots, as well. Femora black, often marked with ivory in male: fore femur with posteroapical spot and (postero-)ventral stripe in apical half, mid femur with anterior stripe in apical third. Anterior surface of all tibiae largely to completely ivory.

Distribution. Canada: newly recorded from ON. Eastern U.S.: NJ and PA south to SC, west to OK and eastern TX (Krombein 1979; newly recorded from SC and TX based on material in DEBU).

Biology. Nests in borings in wood and uses mud for cell partitions and closing plugs. At Rondeau Provincial Park, Ontario, one female was observed scraping dry clay from the disturbed ground of a rarely frequented woodland trail. Prey consists of caterpillars of Tortricidae, Crambidae (Pyraustinae) and Amphisbatidae (Krombein 1967, 1979).

 

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