Leptogastrinae (sometimes called "grass flies") is a monophyletic subfamily taxon of Asilidae with most often small species with an elongated body and which fly generally among vegetation, e.g., grasslands, or “perch on the tips of slender, bare branches, usually with the abdomen extended outward, in alignment with the branch, thus resembling the twig tip” (Fisher 2009: 626) and so their body is well-camouflaged. Leptogastrinae species have peculiar morphological specializations that are adaptations to their behavior for resting and perching on grass stems or twig tips as well as their habit of a helicopter-like hovering flight. This behavior allows them to fly among dense vegetation in search of prey insects or spiders that are captured while resting, which stands in stark contrast to all other Asilidae species that exclusively capture flying prey.
Leptogastrinae are known from 472 species (6.3% of Asilidae diversity) in 17 genera within the world-wide distribution of Asilidae with the notable exceptions of Chile and New Zealand, which otherwise harbor a unique Asilidae fauna of 132 and 19 species, respectively. Although very distinct among Asilidae, Leptogastrinae have not been studied taxonomically and phylogenetically in detail.
The Leptogastrinae LifeDesk provides detailed information on genera and species as well as images of representtaive taxa and can be accessed at: http://leptogastrinae.lifedesks.org.