Hemerobiidae is a family of Neuropteran insects commonly known as brown lacewings. These insects differ from the somewhat similar Chrysopidae (green lacewings) not only by the usual colouring but by the wing venation: hemerobiids having numerous long veins lacking in chrysopids. Some of the costal cross veins are forked, unlike in green lacewings.
The superfamily Hemerobioidea is nowadays restricted to the Hemerobiidae. Formerly, the pleasing lacewings (Dilaridae), silky lacewings (Psychopsidae), giant lacewings (Polystoechotidae) and as noted above the green lacewings (Chrysopidae) were placed therein too. Of these, only the first seem to be reasonably close relatives of the brown lacewings. The silky lacewings in fact seem to belong to an altogether different suborder of Neuroptera, the Myrmeleontiformia.
Numerous fossil Hemerobiidae have been described, some from the still-living genera, others from genera that are entirely extinct today. While most have been found in Eocene to Miocene rocks or amber, Promegalomus is known from the Jurassic. It was formerly considered to constitute a distinct family Promegalomidae, but is nowadays recognized as a very basal member of the Hemerobiidae. The Cretaceous Mesohemerobius was formerly considered a brown lacewing, but is today rather placed as incertae sedis in the Neuroptera; it might be a member of the Hemerobioidea but not even that is certain. Notable fossil Hemerobiidae genera are:
None of these appear to belong to a living subfamily.
Some additional brown lacewing larvae have been found as fossils, but it has been impossible to determine their generic or subfamilial association.