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i finally got a minute to do more research and i now have no doubts that it is L. latipes.

meantime, i found a photo of a species that fits the description of L. halteralis at boldsystems website:
http://v3.boldsystems.org/index.php/Taxbrowser_Taxonpage?taxid=598145

Furthermore, it seems that you have this species documented at bugguide but it is not officially identified as halteralis:
https://bugguide.net/node/view/219972

I will add a note at bugguide.

additional notes:
Irina Brake has a description of latipes which mentions the yellow rings on the tibiae:
http://milichiidae.info/taxonomy/term/385/descriptions

Best wishes,
John