Siphosturmia sp. (French Guiana)
These are 2 Siphosturmia spp. The first looks very like a Winthemia but on closer examination is has 4 katepisternal bristles, not 2.
EDIT (05/10/2010): I am a little suspicious about the second specimen – I think I might have written the wrong name down because the humeral callus has a triangle of bristles, and this should be impossible for Siphosturmia.
Det: Monty Wood, 2010.