Few tyrannids exhibit such striking sexual dimorphism as this tiny and highly attractive Amazonian species. Males fit the species’ vernacular name, being principally black above, with narrow white lores and broad tertial markings, and basically white below, whereas females are fundamentally olive-green above, with the same distinctive markings on the tertials, but are more grayish below, and have a bright rufous crown. Despite their attractive plumage, the birds are most easily located by virtue of their somewhat insect-like tik vocalizations. Also known as the Black-and-white Tody-Tyrant, it is principally distributed in upper Amazonia, in southern Colombia to eastern Peru, and southwest Amazonian Brazil, and has also been found, very spottily across southern and eastern Amazonian Brazil. The species is usually found in bamboo thickets or heavily vine-dominated tangles, and pairs often maintain close contact, but feed apart from any mixed-species flocks that wander through their territories.