214 HOMOPTERA. 



The most familiar insect of this family is Tettigonia Viridis, 

 Linn., a green insect about half an inch long, with a yellow head. 



Family VI. — Ledridce. 

 Hind tibiae with a double row of spines beneath ; body broad, 

 oval ; ocelli placed on the vertex. 



Ledra Aurita, Linn., which may be regarded as the type of this 

 family, is a greenish insect about three-quarters of an inch long, 

 which is found on oaks. Penthimia Atra, Fabr., is a very broad 

 black insect, somewhat resembling a beetle in appearance 



Family VIL — lassidce. 



Hind tibipe with a double row of spines beneath ; body rather 

 long and broad, but narrower than in the Ledridce ; ocelli, when 

 present, placed on the Iront of the head. 



A considerable number of small species are included in this 

 family. The genus Eupelix, Germ., is remarkable for its large 

 flattened head. In Bythoscopus, Germ., the head is also very broad, 

 but is much shorter than in Eupelix, while in the typical genus 

 lassus, Fabr., the head is still less produced. 



Family VIII. — Psyllidce. 



Tarsi two-jointed ; antennae eight- or ten- jointed, terminated 

 by two slender bristles ; ocelli three ; wings transparent, with few 

 nervures ; legs formed for leaping ; larva covered with a cottony 

 secretion. 



These small insects subsist on the sap of plants, to which they 

 are sometimes injurious ; a few species produce galls. Like the 

 Aphidce, to which they are allied, they discharge a fluid of which 

 ants are very fond. Livia Pijri, Linn., a red, long-winged species, 

 abounds on pear-trees in all its stages. 



Family IX. — Aphida-. 



Tarsi two-jointed ; antennae long, five- to seven- jointed ; ocelli 

 absent ; wings transparent, with few nervures (generally absent in 

 the asexual forms) ; legs not formed for leaping. 



The Aphidce or Plant Lice are among the most destructive of 

 all insects. They exist in enormous numbers, smothering the 

 plants on which they feed, both by their mere abundance, and by 

 draining them of their sap, which they discharge in the form of a 

 sweet sticky substance called honey-dew, of which ants are very 



