254 AUSTRALIAN PSYLLIDJi, 



have one species bred from the Kurrajong (Sterculia heteroj)hylla) 

 that, on a superficial examination, is wonderfully like a green- 

 winged aphid. In their larval habits they are much more coccid- 

 like, and some of the lerp-scales produced might very easily be 

 mistaken for a coccus. They seem also to have some relationship, 

 particularly in the larval stages, with the Alewrodidce. Most of 

 the larvae of Aleurodes form rounded disc-like shells or tests under 

 which they pupate, but those of some of the Australian species 

 pit the leaves of Eucalpyts exactly like some Psyllids; however 

 in the adult stage Aleurodes shows a much closer relationship to 

 the Coccids, and might be described as a higher type of this group, 

 with both sexes winged, but with a very primitive venation. In 

 the Psyllidce the venation of the wings is very well-defined, and 

 characteristic of the species. Sharp (11) places the Psyllidce in 

 the sixth family of the Homoptera after the Jassidce and before 

 the Aphidce, a very natural position. In this he follows most of 

 the later systematic entomologists who have placed them from 

 their external characters. 



A great deal has been written about the classification of the 

 Psyllidce. Reaumur named them Faux Pucerons from their 

 relation to the Aphidce. Linnaeus placed them in the genus 

 Chermes (now restricted to a group of the Coccidce). Geoffroy, 

 considering that the later name had been improperly used by 

 Linnaeus, gave them the very appropriate generic name Psylla, 

 from the Greek for a flea, in reference to their jumping powers. 



A number of later papers were written in which Psyllidce. were 

 described, but it was not until 1848 that any regular classification 

 of this family was undertaken. In this year A. Forster (12) 

 defined the different genera, added several new ones, redescribed 

 the old species, and described a great number of others. Dr. 

 Franz Low has been one of the most prolific writers upon this 

 family. In 1878 (14) he divided them into four subfamilies; and 

 in 1882 (15) he published a complete revision of all the described 

 palaearctic species, with their synonomy, followed by a catalogue 

 thereof in the same year, in which he listed over 170 species (16). 



