Neivamyrmex melshaemeri

This species, only known from males, is common at Austin about the electric lights during the spring and summer months (Wheeler 1908). Males have been collected from April to August inclusive, most of them having been taken during June. They are apparently among the earliest males of Neivamyrmex to appear (Smith 1942).

Identification
This common small species can be confused with no other United States species. The long flexuous hairs on the body of this ant readily distinguish it from our other Neivamyrmex. Throughout its range from the southern United States to South America this ant is morphologically quite uniform. (Snelling and Snelling 2007)

Distribution
United States: Louisiana and Oklahoma west to Texas; Mexico: Tamaulipas and San Luis Potosí south to Chiapas and Yucatán; South America. (Snelling and Snelling 2007)

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Costa Rica, Guatemala, Mexico.

Castes
Known only from males.

Nomenclature

 * . Labidus melshaemeri Haldeman, 1852: 368, pl. 9, figs. 7-9 (m.) U.S.A. (Texas).
 * Type-material: holotype male.
 * Type-locality: U.S.A.: Texas, Fort Gates (H. Haldemann).
 * Type-depository: unknown (no type-material known to exist).
 * Combination in Eciton (Labidus): Mayr, 1886d: 442;
 * combination in E. (Acamatus): Emery, 1900a: 187;
 * combination in E. (Neivamyrmex): Smith, M.R. 1942c: 576;
 * combination in Neivamyrmex: Borgmeier, 1953: 8.
 * Status as species: Roger, 1863b: 42; Mayr, 1863: 425; Cresson, 1872: 195; Mayr, 1886d: 442; Cresson, 1887: 259; Dalla Torre, 1893: 4; Emery, 1895c: 261, Emery, 1896g: 33; Forel, 1899c: 28; Emery, 1900a: 178 (in key); Wheeler, W.M. 1908e: 418; Emery, 1910b: 26; Wheeler, W.M. 1910g: 562; Essig, 1926: 869; Smith, M.R. 1938b: 158; Smith, M.R. 1942c: 576 (redescription); Creighton, 1950a: 73; Smith, M.R. 1951a: 780; Borgmeier, 1955: 647 (redescription); Kempf, 1972a: 157; Watkins, 1972: 351 (in key); Watkins, 1976: 23 (in key); Smith, D.R. 1979: 1331; Watkins, 1982: 213 (in key); Watkins, 1985: 484 (in key); Bolton, 1995b: 290; Snelling, G.C. & Snelling, 2007: 479; Branstetter & Sáenz, 2012: 254.
 * Distribution: Costa Rica, El Salvador, Guatemala, Mexico, U.S.A.

Male
Smith (1942) - Length 7 mm.

Head approximately one and six-tenths times as broad as long. Eye prominent, convex, protuberant. Ocelli large; ocellar protuberance concave at summit, inner border of eye and lateral ocellus almost touching each other. Frontal carinae sharply margined, subparallel, with distinct groove between them up to point where each converges outwardly toward eye, thus forming a prominent ridge above each antennal socket. Antennal scape robust, short, approximately as long as combined length of first 3 funicular segments; second funicular segment unusually short, third through fifth distinctly broader than any succeeding segments. A pair of short, stubby, toothlike projections posterior to clypeus, these not evident on all individuals. Mandible rather long, slender, curved, tapering from base toward apex, where it ends in a very acute point. Posterior corner of head strongly projecting between lateral ocellus and inner border of eye, but not so well developed as in fuscipennis. From above, posterior corners of head projecting behind and also dorsolaterad of eye, thus giving head an extended appearance. In profile, vertex and posterior corner of head well extended dorsally above superior border of eye. Eye nearly touching base of mandible, occupying all of side of head except for large, protuberant, ridge-shaped corner posterodorsad of eye. Region of head posterior to ocelli, in profile, flattened or feebly concave; occiput without a perceptible flange. Thorax, in profile, distinctly longer than high, not projecting perceptibly above head. Anterior median and parapsidal lines often indistinct or missing, the former most easily seen. Epinotum, in profile, subtruncate. Tarsal claws faintly toothed. Petiole, in profile, flattened or feebly convex beneath. Gaster elongate, slender, compressed, with distinct constrictions between segments. Intermediate tooth on apex of seventh gastric sternum small and indistinct, the lateral teeth acute. In profile, apex of paramere truncate, ventral border of apex convex, and dorsal border of apex excised.

Body rather shining in spite of the unusually long and fairly dense hairs covering it. Punctures on side of thorax sparse, but visible in some lights.

Hairs yellowish, long, suberect; less appressed on head, thorax, petiole, and ventral surface of gaster; unusually long near apex of gaster.

Yellowish brown to darker brown with the head usually, and the thorax occasionally, darker than remainder of body. Wings dusky grayish or dusky yellowish, with light-brown veim and distinct dark stigma.

Type Material
Smith (1942) - Fort Gates, Coryell County, Tex., Lieut. Horace Haldeman. Type apparently lost. The type locality of this species has been incorrectly cited by many formicologists as Fort Gates, Utah, because melsheimeri was described by Prof. S. S. Haldeman in the report of Stansbury's Expedition to the Great Salt Lake (Haldeman, 1852). Since not all the insects mentioned or described in this report were collected in Utah, and as melsheimeri is common in Texas (no one has ever reported it from Utah), I believe the Fort Gates referred to is unquestionably that in Coryell County, Tex. What applies to the type locality of melsheimeri also applies to the type locality of Neivamyrmex harrisii.

References based on Global Ant Biodiversity Informatics

 * Borgmeier T. 1955. Die Wanderameisen der neotropischen Region. Studia Entomologica 3: 1-720.
 * Dash S. T. and L. M. Hooper-Bui. 2008. Species diversity of ants (Hymenoptera: Formicidae) in Louisiana. Conservation Biology and Biodiversity. 101: 1056-1066
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Fernandes, P.R. XXXX. Los hormigas del suelo en Mexico: Diversidad, distribucion e importancia (Hymenoptera: Formicidae).
 * Hess C. G. 1958. The ants of Dallas County, Texas, and their nesting sites; with particular reference to soil texture as an ecological factor. Field and Laboratory 26: 3-72.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Lachaud J. P., and G. Perez-Lachaud. 2013. Revisión preliminar de las hormigas de Campeche y Quintana Roo, México, con base en la colección de Arthropoda del Colegio de la Frontera Sur. In Formicidae de Mexico (eds. M. Vasquez-Bolanos, G. Castano-Meneses, A. Cisneros-Caballero, G. A. Quiroz-Rocha, and J. L. Navarrete-Heredia) p21-32.
 * O'Keefe S. T., J. L. Cook, T. Dudek, D. F. Wunneburger, M. D. Guzman, R. N. Coulson, and S. B. Vinson. 2000. The Distribution of Texas Ants. The Southwestern Entomologist 22: 1-92.
 * Smith M. R. 1935. A list of the ants of Oklahoma (Hymen.: Formicidae). Entomological News 46: 235-241.
 * Smith M. R. 1936. A list of the ants of Texas. Journal of the New York Entomological Society 44: 155-170.
 * Smith M. R. 1942. The legionary ants of the United States belonging to Eciton subgenus Neivamyrmex Borgmeier. American Midland Naturalist 27: 537-590.
 * Snelling G. C. and R. R. Snelling. 2007. New synonymy, new species, new keys to Neivamyrmex army ants of the United States. Memoirs of the American Entomological Institute 80: 459-550
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Watkins II, J.F. 1982.The army ants of Mexico (Hymenoptera: Formicidae: Ecitoninae). Journal of the Kansas Entomological Society 55(2): 197-247.
 * Watkins J. F., II 1985. The identification and distribution of the army ants of the United States of America (Hymenoptera, Formicidae, Ecitoninae). Journal of the Kansas Entomological Society 58: 479-502.
 * Wheeler G. C., and J. Wheeler J. 1989. A checklist of the ants of Oklahoma. Prairie Naturalist 21: 203-210.
 * Wheeler W. M. 1908. The ants of Texas, New Mexico and Arizona. (Part I.). Bulletin of the American Museum of Natural History 24: 399-485.
 * Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.
 * Young J., and D. E. Howell. 1964. Ants of Oklahoma. Miscellaneous Publication. Oklahoma Agricultural Experimental Station 71: 1-42.
 * Young, J. and D.E. Howell. 1964. Ants of Oklahoma. Miscellaneous Publications of Oklahoma State University MP-71