Red bug with white tips on antennae
I think they are called "Red Bugs" (really), otherwise known as Antilochus conquebertii (aka Antilochus coquebertii).



The black coloring changes from location to location. These were found in India. They were even described by the querent as eating black seeds. 

Viet Nam Red Bugs are pretty as well:




  The family Pyrrhocoridae is commonly called the Red Bug family, and the family includes the Cotton Stainers as well as the Firebugs, so Red Bugs is the more general family name that includes the other genera and species.