Genus Brachymyrmex (Formicinae)

• Brachymyrmex Mayr, G. 1868b: 163. Type species: Brachymyrmex patagonicus Mayr, by monotypy.
• Bryscha Santschi, 1923b: 652 (as subgenus of Brachymyrmex) . Type species: Brachymyrmex pillipes Mayr, by original designation. Synonymy: Brown, W.L. 1973b: 179 (provisional) ; Smith, D.R. 1979: 1424.

• OVERVIEW.   Most species of this genus are found south of the United States. They usually form small colonies in the soil under various objects and are easily transported by commerce in soil or plants. They are fond of honeydew and attend honeydew excreting insects (Smith, D.R. 1979: 1424). These ants are minute and have a very thin integument so that dried specimens often shrivel up. Creighton (1950a: 357) called Brachymyrmex a "miserable little genus", and it is badly in need of revision. There are 3 described Nearctic species, but, in actuality, there may be 10 species in North America (S.P. Cover, personal communication). The yellow forms are all lumped under the name 'depilis.'
• ZOOGEOGRAPHICAL REGIONS.  Neotropical, Nearctic, Palearctic, Malagasy.
• RECOGNITION.   This genus is common and widely distributed although its small size can make it easy to overlook. Brachymyrex is easily separated from other Nearctic genera in Formicinae by the following combination of characteristics: Total length 1.5-2 mm. Integument soft, flexible. Mandible triangular with a more or less distinct basal and masticatory margins. Eye well-developed; usually located near middle of side of head. Antenna 9-segmented. Metanotal impression distinct. Propodeum with basal face very short and a very long, sloping declivitous face. Hairs sparse, often absent on mesosoma.
• TRIBE.  Plagiolepidini.
• REVISIONS.   Wheeler, W.M. 1903c: 102–103 .— Santschi, 1923b: 650–678 (out of date) .
• TAXONOMY.   Smith, M.R. 1943e: 313 (diagnosis of m.) .— Smith, M.R. 1947f: 601–602, pl. 17, fig. 66 (description w., figure (lateral view) of w.) .— Wheeler, G.C. & Wheeler, J. 1953c: 129,139 (larvae) .— Wheeler, G.C. & Wheeler, J. 1970b: 652 (larvae) .— Bolton, 1994: figs. 76, 77 (SEM (full face and lateral view) of w.) .—Bolton, 2003: 276.
• MISCELLANEOUS.   Arnaud & Quate, 1951: 171 (note on swarming) .
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• depilis. Brachymyrmex heeri subsp. depilis Emery, 1893k: 635 (w.q.) . [USA, DC; No types in USA.] Wheeler, G.C. & Wheeler, J. 1953c: 139, pl. II, figs. 10–15 (l.) . Raised to species: Santaschi, 1923b: 663. Note that the original material is not "(w.)" as in Smith, D.R. 1979: 1424.
• nanellus. Brachymyrmex nanellus Wheeler, W.M. 1903c: 102, fig. 7b (w.m.) . [USA, TX, (Austin)] Synonymy: Creighton, 1950a: 359 .
• flavescens. Brachymyrmex depilis subsp. flavescens Grundmann, 1952: 117 (w.) . [USA, UT, Salt Lake Co.; USNM, Univ. of Utah] Synonymy: Cole, A.C. 1953h: 266 .

• DISTRIBUTION. Nova Scotia south to FL west to BC, CA (Smith, D.R. 1979: 1429).
• TAXONOMY. Santschi, 1923b: 664.— Cole, A.C. 1940b: 65.— Gregg, R.E. 1945a: 469 .— Cole, A.C. 1953j: 266.— Wheeler, G.C. & Wheeler, J. 1968a: 210 (larva) .— Warren & Rouse, 1969: 57 (diagnosis of w., habitat, brief natural history, distribution in AR) .
• MISCELLANEOUS. Wheeler, W.M. 1905j: 389 .— Smith, M.R. 1927b: 313.— Dennis, 1938: 469.— Headley, 1952: 436, 439.— Carter, 1962b: 192 (habitat, distribution in NC) .— Gregg, R.E. 1963: 447–449 .— Wheeler, G.C. & Wheeler, J. 1963: 161–163.— Wheeler, G.C. & Wheeler, J. 1973e: 108–109.— Van Pelt, 1983: table 1 (habitat and frequency in the Chisos Mts. Texas) .— MacKay, Lowrie, et. al. 1988: 104 (occurrence in NM) .— Cokendolpher & Francke, 1990: 28 (distribution in TX) .— Rojas-Fernández & Fragoso, 1994: 68 (diagnosis of w., habitat) .
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• musculus. Brachymyrmex tristis r. musculus Forel, 1899h: 124 (w.) . [Costa Rica] Forel, 1901d: 135 (q.) . Raised to species: Forel, 1901d: 135.

• DISTRIBUTION. Louisiana, Costa Rica, Mexico.
• TAXONOMY. Santschi, 1923b: 673.
• MISCELLANEOUS. Wheeler, G.C. & Wheeler, J. 1978a: 189–190 (first occurrence in US) .
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• obscurior. Brachymyrmex heeri var. obscurior Forel, 1893j: 345 (w.q.m.) . [Antilles] Race of heeri: Forel, 1897b: 298; Forel, 1912j: 62. Raised to species: Wilson & Taylor, 1967b: 92.

• DISTRIBUTION. Florida and southern Texas; Mexico, Central Amer., W. Indies.
• TAXONOMY. Santschi, 1923b: 654, 666.— Smith, M.R. 1937: 866–867 (also biol. notes) .
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