Based on the keys in this paper by Melander (1) and comments from Dr. Buck and Martin Hauser, I think this fly may be Chyliza apicalis Loew.

ID’d to Chyliza using the Melander psilid key: “Robust; occiput flat, ocellar triangle small and placed well back; 4 scutellar bristles (can’t see the wing venation well enough to see if they fit the description in this couplet) and the Buck and Hauser comments about “wings that are bent downward at a slight angle just before the middle of the wing” and “Psilidae fly genus Chyliza - the wings are bent in the middle…”, respectively.

ID’d to C. apicalis using the Melander Chyliza key: “Dorsum of thorax yellow” (vs. mostly black), “pleurae more or less yellow” (vs. black and “all femora with apical black ring”), “Upper half of pleurae with black vitta; apex of wings clouded” (vs. “Pleurae entirely yellow; wings hyaline”), and “Apical cloud of wings following the margin, not widened behind, veins two, three and four ending in the cloud; pleurae marked with only the vitta” (vs. a Mexican species with “apex of veins two, three and four not clouded.”)

After all of that, the Melander paper is from 1920 and I’m not sure that his taxonomy is still considered valid. I’d appreciate it if a responsible adult could confirm or correct this ID.

Thanks in advance for the help!

(size estimated from photo. this is the only photo I got of this fly before it disappeared)