In recent years a species of the genus Narnia (Hemiptera: Coreidae) has become a problem as a pest of prickly pear cactus or ‘nopalitos,’ Opuntia ficusindica, in Milpa Alta, in the south of Mexico City, which is the most important production region of this vegetable in the country. A survey of Narnia in Milpa Alta during the years 2010 and 2011 has resulted in the first report, to our knowledge, of Narnia femorata Stål. This insect should be monitored and considered in future studies to identify the family Coreidae that can cause damage on O. ficus-indica.