Allokermes galliformis (Riley) (Hemiptera: Kermesidae), sometimes referred to as the ‘pin oak kermes’, has emerged as a significant pest of red oaks grown in the Front Range area of eastern Colorado. Although kermes scales infrequently cause significant tree damage, a novel association exists between the pin oak kermes and the pathogenic bacterium Lonsdalea quercina subsp. quercina. Together, they produce drippy blight disease of red oaks which is characterized by significant branch dieback. Field studies were conducted in Boulder, CO during 2015–2016 to better understand the life history of A. galliformis and identify points when this insect may be best managed. A. galliformis has a 1-yr life cycle. Upon egg eclosion in September and October, crawlers migrated to textured places on limbs to overwinter. In May, a second migration occurred with the great majority of first instar females moving to new growth and the base of the current season growth where they permanently settled, became sessile and resembled plant galls. Immature male scales remained active and ultimately migrated to the trunk or solid surfaces in the near vicinity of the trunk, produced a cocoon, and subsequently emerged as winged forms in early summer. After mating, females began to produce eggs and peak egg production occurred between mid-August and mid-September when adult females produced an average of 2,488 and 4,726 eggs in 2015 and 2016, respectively.