Characteristics
Sobarocephala quadrimaculata is a distinct species with a densely plumose arista, four spots on the scutum (hence the specific name), a dark scutellum and epandrium, and an anterodistal spot on the wing that appears to be "smudged" towards the posterior margin. The surstylus is subquadrate with long, stout palisade-like bristles and the distiphallus is long and spoon-shaped, not thin along its length like that found in most other Sobarocephala.

Similar species
The species most similar to Sobarocephala quadrimaculata in North America is S. cruciger, which has a similar arista, head and colour pattern. The scutellum and epandrium are entirely brown in S. quadrimaculata, however, as is most of tergites 3,4 and 6. In addition to the supra-alar spots there is also one pair of anterolateral spots (not one pair of posteromedial spots) and the surstylus is subrectangular, not pointed.

Sobarocephala affinis and S. muesebecki also have a densely plumose arista, but the sides of the frons are parallel (not converging posteriorly), the ocellar bristles are well-developed (not minute), the face is flat and the thorax is entirely yellow.

Distribution
Sobarocephala quadrimaculata is only found in and around Florida and eastern Texas in North America, but it is much more widespread in the tropics, occurring in the Bahamas, Colombia, Costa Rica, Mexico, Nicaragua and Panama.