410 



AN INTRODUCTION TO ENTOMOLOGY 



wavy red lines on the fore wings. It measures about 8 mm. to the 

 tips of the wings, and Hves upon the leaves of grape-vines, oaks, and 

 hickor}^ 



Ormenis. — In our common representatives 

 of this genus the wing -covers are broad, and 

 closely applied to each other in a vertical 

 position ; they are more or less truncate, and 

 give the insects a wedge-shaped outline. 0. 

 septentriondlis (Fig. 481) is a beautiful, pale 

 green species powdered with white, which 

 feeds on wild grape-vines, drawing nourish- 

 ment from the tender shoots and midribs of the 

 leaves, during its young stages. 



Fig. 481. — Ormenis sep- 

 tentrionalis. 



Family CHERMID^* 



The Jumping Plant-Lice 



The jumping plant-lice are small insects ; many of them measure 

 less than 2 mm. in length ; and the larger of our species, less than 5 mm. 

 They resemble somewhat the winged aphids; but they 

 look more like miniature cicadas (Fig. 482). They 

 differ from aphids in the firmer texture of the body, 

 in the stouter legs, in having the hind legs fitted for 

 jumping, and in the antennas being ten -jointed or 

 rarely nine- or eleven-jointed. The terminal segment 

 of the antennae bears two thick setae of unequal length. 

 Both sexes are winged in the adult. The front 

 wings are ample, and, while often transparent, are much 

 thicker than the hind wings. The homologies of the 

 wing-veins of the fore wings of Psyllia fioccosa are indi- 

 cated in Figure 4S3 . 



Fig. 482 

 lia. 



-Psyl- 



itf.+2 



Fig. 483. — The venation of a fore wing of Psyllia floccosa. (After Patch.) 

 The beak is short and three-jointed. The basal segment of the 

 beak is held rigidly between the fore coxa. 



*This family has been quite commonly known as the Psyllidae, a result of an 

 incorrect application of the name Chermes to a genus of the Phylloxeridae. 



