Pyramica eggersi (Emery 1890)

Dacetini, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view

Additional Images: line drawings of worker face and anterior view of apical fork of mandible (image); line drawings contrasting presence of spongiform appendages between gundlachi and eggersi (image).


Full Range: Throughout mainland tropical America from southern Brazil to southern Mexico, on many Caribbean islands, and in southern Florida.

Costa Rican Range: Atlantic and northern Pacific lowlands (possibly exotic, see below).


Mandibles in full-face view linear, elongate and narrow; leading edge of scape with freely projecting hairs; inner margin of mandible without a tooth or distinctly enlarged denticle at or near the midlength; labral lobes short, trigger hairs at apices of lobes long; apical fork of mandible small, with two tiny intercalary denticles; mandibles straight, with weakly convex inner borders, each bearing 4-8 minute denticles on distal 1/3 to 1/2; spongiform appendages of petiole and postpetiole obsolete; first gastral tergum superficially reticulate-punctulate and opaque in front, becoming indefinitely shagreened and weakly shining behind. Also see Bolton (2000:184).

Head length 0.40-0.45mm, mandible length 0.23-0.28, CI 81-86, MI 58-65 (n=20 workers, Bolton 2000).

Similar species: gundlachi, subedentata, trieces.

Natural History

Members of the genus are all predaceous, with a static pressure mode of attack (Bolton 1999).

Brown (1960) reported

Weber found specimens in a compost heap in the Botanical Garden at Roseau, Dominica, and in an island of vegetation growing in the Pitch Lake of Trinidad; also on Trinidad, he took a sample from low-growing epiphytes in second-growth forest. Kempf sifted specimens from humus in Sao Paulo. Indications are that this species can stand more dryness than many dacetines, and its presence in many culture areas suggests that it is spreading rapidly through nursery stock transport and other human commerce.

He suggested that southern Brazil and Bolivia was its home range, and that elsewhere it had been introduced.

In Costa Rica this species appears rare, although my collecting has not emphasized dry and/or synanthropic habitats. I have encountered it in Winkler samples from Finca La Pacifica (riparian forest in seasonally dry region), and La Selva Biological Station (lowland rainforest).

Original Description

Strumigenys eggersi Emery 1890:69, pl. 7, fig. 9. Syntype worker, queen: Antilles Islands, St. Thomas Island (Eggers) [NMV, MZSP, USNM].

Later moved to Pyramica. See Bolton (2000) for complete synonymy.

Literature Cited

Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). Journal of Natural History 33:1639-1689.

Bolton, B. 2000. The ant tribe Dacetini, with a revision of the Strumigenys species of the Malagasy Region by Brian L. Fisher, and a revision of the Austral epopostrumiform genera by Steven O. Shattuck. Memoirs of the American Entomological Institute 65:1-1028.

Brown, W. L., Jr. 1960 (1959). The neotropical species of the ant genus Strumigenys Fr. Smith: Group of gundlachi (Roger). Psyche 66:37-52.

Emery, C. 1890. Studii sulle formiche della fauna neotropica. Bull. Soc. Entomol. Ital. 22:38-80.

Page author:

John T. Longino, The Evergreen State College, Olympia WA 98505

Date of this version: 7 May 2001
Previous versions of this page: 16 April 1997
Go back to top

Go to Ants of Costa Rica Homepage