This taxon group contains at least 7 species ranging in size, with a light brown ground colour, broad bodies and darker coloured abdomens. They have plumose antennae and quite a strong subscutellum but, after checking with the Manual of Central American Diptera (Brown et.al., 2009), it appears that most of them belong to the subfamily Mesembrinellinae (Calliphoridae). In Europe having a rounded subscutellum would virtually guarantee that it was a tachinid but in the neotropics that feature cannot be fully relied upon. The Mesembrinellinae have hairs under the scutellum and a differently-shaped metathoracic spiracle with secondary features such as the strongly curved median vein and the plumose antennae.
As you can see, the second taxon (type-c) is very different from the rest – having completely different wing venation and strong bristles on the abdomen. This suggests that it really is a tachinid this time so it will be the first to be split off from fg-taxon #16 but for now it stays here due to its rough similarity to the others.
EDIT (Monty Wood 26/9/2010): Monty has not seen enough of a difference between the supposed genera to keep most of them. So he currently places them all within Mesembrinella.
EDIT (15/10/2010): Taxon “type-d” on re-examination turns out to be a tachinid called Daetaleus – it lacks the white hairs under the scutellum and funny-shaped metathoracic spiracle of the Mesembrinellinae.