Cyllecoris histrionius is a species of bug in Miridae family that can be found in the United Kingdom, Iceland, Western, Eastern, and Central Europe. The species have strikingly marked and elongated body, and have a large black pronotrum that is narrowed at the front and is of yellowish-white colour. The eggs hatch in spring after they overwinter for a bit. The species hatch as bluish-green coloured larvae. Adults fly from May to July and could be found on oaks feeding on small insects such as aphids and bark flies.