The Adelgidae is a small family of the Hemiptera closely related to the aphids, and often traditionally included in the Aphidoidea with the Phylloxeridae. Adelgids are often known as "woolly conifer aphids". The family is composed of species associated with pine spruce or other conifers, known respectively as "pine aphids" or "spruce aphids". This family includes the former family Chermesidae, or "Chermidae", the name of which was declared invalid by the ICZN in 1955. There is still considerable debate as to the number of genera within the family, and the classification is still unstable and inconsistent among competing authors.