The difficult Machimus genus can be tough anywhere in the south. On this page are five of the species in our area. Above left is M. antimachus. And right is M. prairiensis. M. antimachus may have the most wing darkening of any of the species. And it is the main species in the east with the femora mostly orange.  M. prairiensis is usually very clear winged.  M. prairiensis has the orange limited to the distal femur and proximal tibia. 

Machimus snowii in the above left is the species that sticks closest to wet lands and even swamps. Most of the other species are dry land and upland or prairie species. Note the contrast between orange tibias and darker femurs. On the right is notatus which is the darkest overall with almost all black legs.  M. notatus is a spring species and often one of the first robbers out in some areas after the Laphria. We seem to have M. virginicus which is also darkish and separated from notatus by genitals mostly.  M. sadyates is also dark legged with a much darker upper mystax (not pictured here).

This is Machimus erythocnemius. Also a mostly open land species here (though Norm has found one in his front yard). Has prominent orange femur rings. And lacks the white hair on the femurs of the snowii and antimachus. Though the bristles on the fore femora are mostly white and weaker. Appears more golden or reddish than all except the top right prairiensis species. This species can be confused with paropus (not pictured) which has an all black metafemora and strong black bristles on the forefemora.