1) Feeds on plant juices 2) Jumping plant louse 3) Louse 4) Plant louse 5) Psyllid 1) Psyllid 
Psylla (from the Greek psulla, meaning flea) is a genus of sap-sucking insects belonging to the order Hemiptera. Twelve species are within the genus, each with a specific host. Some harmful species commonly known as flies belong to neighbouring genera, such as Cacopsylla (which includes most of the pyslla harmful to fruit trees), the Albizia fly (...
• (n.) Any leaping plant louse of the genus Psylla, or family Psyllidae.
Psyl'la noun ; plural Psyllæ . [ New Latin , from Greek ... a flea.] (Zoology) Any leaping plant louse of the genus Psylla , or family Psyllidæ . 
psyllid, psylla 1. A jumping plant-louse belonging to the family Psyllidae, that includes several species that damage plants by causing galls or spreading virus diseases. 2. A pest that infests pear trees.