[Order] Hemiptera Linnaeus, 1758 - true bugs Suborder Sternorrhyncha Amyot & Audinet-Serville, 1843 - aphids, psyllids, whiteflies and scales Infraorder Aphidodea Superfamily Phylloxeroidea Herrich-Schaeffer, 1854 Family Adelgidae (Annand, 1928) - adelgids Subfamily Adelginae Genus Adelges Vallot, 1836 Subgenus Aphrastasia Börner, 1909 Adelges tsugae Annand, 1924 - hemlock adelgid