Potent predators for their size (note the powerful beak), Assassin Bugs mostly eat other insects. They inject digestive fluid into prey, and suck out their victims' juices.
This group is well represented in Madagascar, where many species sport warning coloration. This one seems to give potential prey, as well as other predators, plenty of opportunity to notice it.
Its less colorful relative, the large, dark Wheel Bug (1 1/4-inch-long Arilus cristatus) can be found in the eastern United States.