gaster
gaster armed with acidopore
gaster armed with acidopore
A small circular opening or orifice at the tip of the gaster used to expel formic acid as part of the defensive and communication system. When present the acidopore is generally surrounded by a fringe of short hairs or setae and is easily seen. In a few species the fringe of hairs is lacking and the acidopore can be difficult to detect. This structure is found only in the subfamily Formicinae and occurs in all genera within this subfamily (Shattuck, 1994).
gaster with dense pubescence
gaster with dense pubescence 
gaster with dense pubescence (Nylanderia)
gaster armed with ventral slit
gaster armed with ventral slit
The tip of the gaster has a transverse slit-like incision capable of excreting chemicals used for defense and communication. This character separates Dolichoderinae from all other subfamilies of ants.
gaster armed with sting
gaster armed with sting
A slender, pointed sting used for hunting and defense is located at the apical end of the gaster. Sometimes it is not fully extruded and difficult to see. Used in Antkey to separate all other subfamilies from Dolichoderinae and Formicinae.
gaster lacking tubercles on first segment
gaster lacking tubercles on first segment
Gaster with tubercles on first segment. Used in Antkey to separate Atta from Acromyrmex.
gaster with tubercles on first segment
gaster with tubercles on first segment
Gaster with tubercles on first segment. Used in Antkey to separate Acromyrmex from Atta.
gaster with furrows
gaster with furrows
First segment of the gaster (abdominal segment 3) with deep parallel longitudinal furrows running the length of the segment. Used in Antkey to separate Gnamptogenys from other genera.
gaster lacking furrows
gaster lacking furrows
First segment of the gaster (abdominal segment 3) variously sculptured, but never with deep parallel longitudinal furrows running the length of the segment. Used in Antkey to separate various other genera from Gnamptogenys.
gaster with erect hairs
gaster with erect hairs
gaster with erect hairs
gaster with sparse pubescence
gaster with sparse pubescence
The first gastral tergite is marked by only sparse pubescence, giving it a shiny appearance. Used in Antkey to separate Brachymyrmex heeri and Brachymyrmex patagonicus from Brachymyrmex minutus and Brachymyrmex obscurior. Also used to separate all other Nylanderia from Nylanderia bourbonica, Nylanderia fulva and Nylanderia vaga.