any of various homopterous insects of the family Adelgidae, as Adelges abietis(spruce gall aphid) and Pineus pinifoliae(pine leaf aphid), that feed and form galls on conifers.
Origin: < NL Adelgidae, equiv. to Adelg(es) a genus name (appar. < Gk ádel(os) unseen, invisible (a-a-6+ dêlos visible, clear) + NL -ges < ?: unexplained by the name's originator) + -idae-id2
[uh-del-jid] 
dʒɪd