What makes thread-winged lacewings different from other lacewings?

Thread-winged lacewings (family Nemopteridae) are distinguished from other lacewings primarily by their highly specialized morphology. Unlike most other neuropterans, their heads are prolonged into a snoutlike rostrum.1

The most striking difference, however, lies in their wings: while most lacewings have two pairs of similar wings, thread-winged lacewings possess posterior wings that are greatly elongated, ribbonlike, or threadlike, often reaching twice the length of the anterior wings. In some species, these elongated hindwings are expanded distally, giving them a distinct spoonlike appearance. Additionally, their larvae are physically distinct from other neuropterans, often featuring a unique, elongated neck formed by the anterior portion of the prothorax.1