THE JUMPING PLANT-LICE OR FLEA-LICE 



(Family Psyllidcz.) 



These insects have two-jointed tarsi, antennae eight-or-nine- 

 jointed, and the hind legs with somewhat swollen thighs. Their 



Fig- '53- — Galls of Pachypsylla venusta O. S. (Alter Riley ) 



Jumping habit distinguishes them from the plant-lice as indicated 

 in the popular name. Certain species exude quantities of the 

 sweet liquid known as honey-dew, which is also abundantly 

 secreted by the plant-lice and by some of the tree-hoppers and 

 leaf-hoppers. Many forms live in galls and there are several 

 species which produce galls of different kinds upon the trees of 

 the genus Celtis, commonly known as " hackberry trees." 



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