1) Arthropod family 2) Family adelgidae 3) Plant lice 
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`...
[n] - plant lice
family Adelgidae noun plant lice