Stylogaster

Taxobox | name = Stylogaster
regnum = Animalia
phylum = Arthropoda
subphylum = Hexapoda
classis = Insecta
subclassis = Pterygota
infraclassis = Neoptera
superordo = Endopterygota|
ordo = Diptera
subordo = Brachycera
zoosubsectio = Acalyptratae
superfamilia = Conopoidea
familia = Conopidae
subfamilia = Stylogastrinae
genus = "Stylogaster"
genus_authority = Macquart, 1835
subdivision_ranks = Species
subdivision = many

The conopid genus "Stylogaster" is a group of unusual flies, restricted to the New World, a few species of which are found in North America. It is the only genus in the subfamily Stylogastrinae, which some authorities have historically treated as a separate family Stylogastridae (or Stylogasteridae).

Stylogastrines are obligate associates of army ants, using the ants' raiding columns to flush out their prey, ground-dwelling Orthoptera and/or roaches. Stylogastrines are somewhat atypical for conopids, in that the egg itself is shaped somewhat like a harpoon, with a rigid barbed tip, and the egg is forcibly jabbed into the host. The female of some species waits for army ants to flush out a target, then she dives in and jabs an egg into the host. The "Stylogaster" larvae then develop as internal parasites. This is a remarkably high-risk behavior, in that many hosts are captured and killed by the ants after a female has laid an egg in it, so many eggs are lost.

Stylogastrines can be found from the Neotropics to Canada. Adults can occasionally be found at flowers, feeding on nectar with their proboscis, which is longer than the body when unfolded. The female's abdomen is also folded under the body, and is the derivation of the generic name ("Stylogaster" = "needle-tail").