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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


Next species | Previous species | Key Euodynerus crypticus Euodynerus crypticus

27. Euodynerus crypticus (Say, 1823)
Figs B5.23, 28, 57; C27.1–7.

Euodynerus crypticus
Euodynerus crypticus Euodynerus crypticus Euodynerus crypticus Euodynerus crypticus
Euodynerus crypticus

Species recognition. Euodynerus crypticus can easily be recognised by colour characters alone. It is the only Euodynerus in the northeast lacking black markings on the scape and pedicel (in other species upper surface with a black streak, rarely very reduced in E. annulatus and E. castigatus), largely ferruginous pronotum, with ferruginous area extending to pronotal hind corner (in other species pronotum black posteriorly except, very rarely, in E. annulatus), largely ferruginous scutellum, ferruginous spot rarely interrupted medially (in other species scutellum black, or black with yellow spots, or black, yellow and ferruginous; very rarely with two ferruginous spots in E. auranus and E. castigatus) and lacking distinct apical fascia on female tergum 2, i.e., apical fascia ill-defined, brown or amber, sometimes yellowish brown (in other species yellow apical fascia always well developed). Structurally, E. crypticus is distinguished from other species by the ventrally long-haired male fore trochanter (hair length over one mid ocellar diameter; hairs erect with bent tips), contrasting with short-haired ventral surface of fore femur (in other species hairs of ventral surface of fore trochanter and fore femur uniform, either both short- or both long-haired), by the deeply depressed vertex around the female cephalic foveae (area around cephalic foveae flattened in other species, at most slightly and gradually depressed below level of vertex), and the very long apical tooth of the female mandible (see key, character shared by E. annulatus).

Variation. Fore wing length 9.5–11.5 mm (♂♂), 13.5–15 mm (♀♀). Pale markings of head mostly yellow in male (excluding ferruginous postocular spot), mostly ferruginous in female (excluding small yellow spot at base of mandible). Female clypeus usually ferruginous with black dorsal and lateral margin, sometimes black with ferruginous apex and a pair of large dorsal ferruginous spots. Postocular spot extending to at least level of middle of eye, in female often extending across whole gena from level of upper eye margin to base of mandible. Female vertex often with additional small to large ferruginous spot between cephalic foveae and upper eye margin, often confluent with postocular spot. Scape ferruginous, with yellow lower surface in male. Dorsal surface of pronotum largely ferruginous; yellow pronotal band usually restricted to middle third, in male often better developed and extending to humeral angle; black markings usually restricted to anterior and lateral surfaces, rarely occupying lateral third or fourth of dorsal surface. Mesopleuron with or without ferruginous dorsal spot. Female scutum sometimes with a pair of small, closely approximated ferruginous spots in posterior half. Scutellum usually ferruginous with black margin, sometimes black with a pair of large ferruginous spots. Metanotum with transverse yellow band, sometimes interrupted medially or suffused with ferruginous. Propodeum with a pair of ferruginous dorsal spots, in female usually extending to propodeal angle or extending along propodeal ridge ventrally, rarely completely absent or with a small yellow spot within (male only). Apical fascia of tergum 1 usually with broad ferruginous border along inner margin of lateral forward extension, rarely without ferruginous markings. Apical fasciae practically absent on following terga in female, at most yellowish brown and ill-defined, present on tergum 2 and usually 3 in male. Male sternum 2 usually with posterolateral yellow spots or apical fascia, spots sometimes also present on sternum 3. More or less extensive ferruginous areas often developed on segment 2 and following in specimens from eastern U.S., absent from the few known Canadian specimens.

Distribution. Canada: ON, AB. Eastern U.S.: CT and NY south to GA, west to WY, UT, AZ (Bequaert 1940b, Krombein 1979). Mexico: south to Oaxaca (Rodríguez-Palafox 1996). Based on the extent of ferruginous markings northeastern populations were divided into two (probably unjustified) subspecies (Bequaert 1940b): the nominate subspecies (extensive ferruginous markings) and ssp. balteatus (Say, 1837). Subspecies stricklandi (Bequaert, 1940) ranges from AB to SD and CO.

Biology. Nests in small colonies in the ground. Burrows are vertical and brood cells are separated by clay partitions. Females make frequent trips to water sources while digging. As in many other ground-nesting Eumeninae the water is used for softening the hard-packed soil in which the nest is built (Isely 1914). Prey consists of caterpillars of Hesperiidae (Krombein 1979).


Next species | Previous species | Key Ancistrocerus unifasciatus Ancistrocerus unifasciatus


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Euodynerus crypticus Euodynerus crypticus