94 



ORDER HEMIPTERA 



membranous or opaque, but homogeneous wings; tlie second 

 liaving the front wings thickened at the base and membranous 

 at the apical portion. The Heteroptera are often given first 

 as if more primitive, but the Homoptera appear to have the 

 most fundamentally primitive character. The venation 

 of the wings and the position of the head particularly seem 

 of more primitive character than in the Heteroptera. 



The third group, Parasita, includes the suctorial lice; 

 the wings are lost, beak is single-jointed, and sette are very 

 much elongated and tubular. They are restricted to the 

 warm-blooded vertebrates, mammals. 



Fiu. .52. — The periodical eicadii (Tihiccn scptcndccem): n, adult; b, 

 same, side view; c, shed pupal skin. Nat\iral size. (After Mailatt, Bur. 

 Ent.. U. S. Dept. Ag.) 



The Homoptera are divided into two divisions, Auch- 

 enorhynchi and Sternorhynclii. In the first group the beak 

 is free, not attached to the sternum, and may be moved 

 readily from the head as its base. In the second grouj) it 

 is fused into the sternum and the base connected with the 

 head at about right angles to the sternum. This latter is 

 a s])ecia]ized condition and must be derived from the simpler 

 condition where the beak is free. 



In the Auchenorhynchi the Cicadidte are one of the most 

 prominent families, which is apparently rather generalized 

 in its features. They show specialization in their life his- 



