Microstylum galactodes
Loew, 1866
Giant Gray Robber Fly
Microstylum galactodes is a large robber fly in the Asilidae, native to the southcentral and southwestern United States. It is one of two North American in the Microstylum, distinguished from the larger M. morosum by its milky white wing , reddish-brown body coloration, and even whitish pruinescence covering the and thoracic dorsum. The species is primarily associated with short grass prairies and scrub lands, showing a more western distribution than its . It was described by Loew in 1866.
Pronunciation
How to pronounce Microstylum galactodes: //ˌmaɪ.kroʊˈstaɪ.ləm ɡəˈlæk.toʊˌdiːz//
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Distinguished from Microstylum morosum by: (1) milky white wing (vs. black to brown in M. morosum); (2) even whitish pruinescence covering entire and thoracic dorsum (vs. pruinescence restricted to lateral margins of in M. morosum); (3) generally smaller body size; and (4) reddish-brown body coloration (vs. black to brown in M. morosum). Both share the characteristic mystax of stout bristles confined to the oral margin.
Appearance
Large, robust robber fly with milky white wing and reddish-brown body. and thoracic dorsum evenly covered with whitish pruinescence (powdery bloom). Mystax (facial beard) confined to oral margin and composed of stout bristles. Generally smaller than the related M. morosum.
Habitat
Short grass prairies and scrub lands. Shows more specific preference than M. morosum, with which it is broadly sympatric.
Distribution
Southcentral to southwestern United States, with a western shift compared to M. morosum. Extends north into western Oklahoma and western Kansas. Documented from Texas and nearby Woodward County, Oklahoma.
Ecological Role
Aerial as . Specific prey records have not been documented for this , though robber flies in this size class typically capture large flying insects.
Human Relevance
Collected as specimens for entomological study. No documented economic or medical significance.
Similar Taxa
- Microstylum morosumLarger with black to brown wings, thoracic pruinescence restricted to lateral margins, and broader eastern distribution into Arkansas and Missouri. Both share the diagnostic mystax structure.
More Details
Taxonomic Note
The Microstylum belongs to the Dasypogoninae (or treated as Leptogastrinae in some classifications). Only two occur in the United States: M. galactodes and M. morosum. The genus reaches greater diversity in the Neotropics.