Atta

differ from the last only in its short palpi, head of neuters usually very large ..

I possess 6 species of Ants, all of small size, which appear to be-long to this genus, having a sting, two knots in the first sigment of the abdomen, antennae not concealed in a cleft, thorax without spines, and short palpi.

Este género , summamente importante sob o ponto de vista económico , precisava ser revisto. Infelizmente é raro encontrarem-se nas collecções representantes de todas as castas( operários , femea, machos) provenientes de um só ninho, o que difficulta muito o estudo taxonomico, porque os caracteres genitaes do macho não podem ser sufficientemente aproveitados para a discriminação das espécies .

Apresento aqui uma lista das espécies , subespécies e variedades conhecidas até hoje, incluindo as formas novas abaixo descriptas.

Formica , pt., Linn. Syst. Nat. i. 962 (1766).

Atta , St. Farg. Hym. i. 173 (nec Fabr.) (1836).

Myrmica , pt., Nyl. Form. Fr. et d'Alger. 83 (1856).

Maxillary palpi 4-jointed, labial palpi 3-jointed; antennae 12- jointed in the female and worker, 13-jointed in the male. Wings longer than the body, with one marginal and three submarginal cells, the third sometimes incomplete; the second submarginal cell bell-shaped, the nervure at its apex uniting with that at the base of the marginal cell. Abdomen with two nodes in the petiole; the large workers usually with enormously developed heads, the small workers with heads of the ordinary size. Pl. IX. fig. 24.

It is very probable, that were the palpi of all the species included in this catalogue examined, they would not agree in the number of joints given in the generic characters of Atta , and at a future time it may be necessary to remove some into the genus Solenopsis , or to establish new genera for their reception; it will be observed that in many instances only one sex has been examined, and frequently only single examples; we have therefore included in the present genus all those forms which appear to have a close relationship to the type, Formica barbara of Linnaeus.