A cluster of sawfly larvae resting on a eucalyptus branch

Perga dorsalis is a sawfly from the Australasian region. When young, the larvae are so gregarious they are often found in a knotted ball of many individuals. When disturbed, they all wriggle their tails and exude a nasty yellowish fluid from their mouths. This latter habit has given them the common name of "Spitfires".