Introduction
Dolichoderus species found in the U.S are small to medium sized ants. They are atypical compared to other North American Dolichoderinae in that the integument is harder, and not as thin and flexible as in our other Dolichoderine genera. Additionally, they can be characterized by having strong sculpture on the alitrunk, and by the declivious face of the propodeum being strongly concave (see side view above). Species found in the U.S. possess "repugnatorial" glands, which produce a pungent or smoky smelling volatile secretion (Creighton 1950).

Taxonomic History (provided by Barry Bolton, 2015)
Wheeler, 1905: 311 (q.m.); Wheeler & Wheeler, 1951: 175 (l.). Combination in Dolichoderus: Mayr, 1886: 436; in Dolichoderus (Hypoclinea): Emery, 1894: 229. Senior synonym of Dolichoderus borealis: Emery, 1895: 330; of Dolichoderus inornatus: Creighton, 1950: 335. See also: Wheeler & Wheeler, 1966: 727; Smith, 1979: 1416; Johnson, 1989: 3; MacKay, 1993: 81; Shattuck, 1994: 61.

Identification
Worker: Medium sized, about 3.5 to 4.0 mm in total length; mesosomal length approximately 1.15 mm; HW about 0.8 mm; and HL about 8.3 mm. Head dark brownish black to black, mesosoma and waist orangish brown, gaster with large yellowish brown to orangish brown patches on first and second tergites with remainder of gaster brownish black, and mandibles, antennae and legs orangish brown. Head almost as wide as long. Mesonotal groove deeply impressed. Propodeum raised, strongly arched, posterio-dorso region thickened and projecting posteriorly (in lateral view), overhanging the strongly concave declivious face. Propodeum longer than wide in dorsal view; posterior edge entire, not notched. Head and dorsum of mesosoma strongly sculptured with numerous well defined foveolae; pronotum and mesonotum with similar amount of sculpture; sides of pronotum with granulate sculpture; mesopleurae with granulation between striations; concavity of the declivious face of propodeum lacks sculpture and is smooth; petiole granulate dorsally and anteriorly to smoother ventrally and posteriorly; and gaster smooth and shiny. Head and dorsum of mesosoma with numerous stout, erect setae; gaster with scattered slightly flexuous setae that are longer than those on head and mesosoma.

Biology and Economic Importance
Based on specimen records and collections in the southeastern US, D. plagiatus appears to prefer upland, mountainous type habitats, rather than being found in the Coastal Plain.

According to Creighton (1950), this species has small colonies (hundreds of workers). Nests are found in soil under detritus in forests, in hollow stems, and in curled-up leaves. They are found in a variety of habitats including open grassy areas, forests, and wet areas. Similar to other Dolichoderus species, they collect the sweet secretions produced by various homopterans and eat other insects for sustenance.

Distribution
Widely distributed from New Brunswick, Canada westward through Ontario, Manitoba, and North Dakota, and southward in the eastern U.S. to Georgia and Tennessee (Cole, 1940; Smith, 1979). In the southeastern US is has been reported from AL, GA, NC, SC, and TN.

Literature Cited
Bolton, B. 2015. An online catalog of the ants of the world. Online at: http://antcat.org. Accessed 1 December 2015.

Cole, A. C.  1940. A guide to the ants of the Great Smoky Mountains National Park Tennessee.  The American Midland Naturalist 24: 1-88

Creighton, W. S. 1950. The ants of North America. Bulletin of the Museum of Comparative Zoology 104:1-585. 

Emery, C. 1894. Studi sulle formiche della fauna neotropica. VI-XVI. Bullettino della Società Entomologica Italiana 26:137-241.

Emery, C. 1895. Beiträge zur Kenntniss der nordamerikanischen Ameisenfauna. (Schluss). Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Tiere 8:257-360.

Johnson, C. 1989. Identification and nesting sites of North American species of Dolichoderus Lund (Hymenoptera: Formicidae). Insecta Mundi 3:1-9.

MacKay, W. P. 1993. A review of the New World ants of the genus Dolichoderus (Hymenoptera: Formicidae). Sociobiology 22:1-148. 

Mayr, G. 1870b. Neue Formiciden. Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 20:939-996. 

Shattuck, S. O. 1994. Taxonomic catalog of the ant subfamilies Aneuretinae and Dolichoderinae (Hymenoptera: Formicidae). University of California Publications in Entomology 112:i-xix, 1-241.

Smith, D. R. 1979. Superfamily Formicoidea. Pp. 1323-1467 in: Krombein, K. V.; Hurd, P. D.; Smith, D. R.; Burks, B. D. (eds.) 1979. Catalog of Hymenoptera in America north of Mexico. Volume 2. Apocrita (Aculeata). Washington, D.C.: Smithsonian Institution Press, pp. i-xvi, 1199-2209. 

Wheeler, W. M. 1905. The North American ants of the genus Dolichoderus. Bulletin of the American Museum of Natural History 21:305-319.

Wheeler, G. C.; Wheeler, J. 1951. The ant larvae of the subfamily Dolichoderinae. Proceedings of the Entomological Society of Washington 53:169-210.

Wheeler, G. C.; Wheeler, J. 1966. Ant larva of the subfamily Dolichoderinae: supplement. Annals of the Entomological Society of America 59:726-732.

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