134 AN INTRODUCTION TO ENTOMOLOGY. 



B. Tarsi one-jointed ; adult male without any beak and with only two wings : 

 female wingless, with body either scale-like or gall-like in form, or grub- 

 like, and clothed with wax. The waxy covering may be in the form of 

 powder, of large tufts or plates, of a continuous layer, or of a thin scale 

 beneath which the insect lives. 2. COCCID.E. 



BB. Tarsi usually two-jointed; wings, when present, four in number. 



C. Wings opaque, whitish ; wings and body covered with a whitish pow- 

 der. 3. ALEYRODID^. 



CC. Wings transparent. 



D. Legs long and slender, not fitted for leaping ; antennae three- to 

 seven-jointed. 4. APHIDID^E. 



DD. Hind legs fitted for leaping; antennae nine- or ten-jointed. 



5. PSYLLID^:. 



AA. Beak evidently arising from the mentum ; tarsi three-jointed ; antennae 

 minute, setiform. 



B. With three ocelli, and the males with musical organs. Usually large 

 insects, with all the wings entirely membranous. 7. CICADID^E. 



BB. Ocelli only two in number, or wanting ; males without musical organs. 

 C. Antennas inserted on the side of the cheeks beneath the eyes. 



8. .FULGORID^E. 



CC. Antennae inserted in front of and between the eyes. 



D. Prothorax prolonged into a horn or point above the abdomen. 



6. MEMBRACID^E. 

 DD. Prothorax not prolonged above the abdomen. 



E. Hind tibiae armed with one or two stout teeth, and the tip crowned 



with short, stout spines. 9. CERCOPID^. 



EE. Hind tibiae having a double row of spines below. 10. 



Family II. COCCID.E.* 

 (Scale-insects or Bark-lice, Mealy-bugs, et at.) 



The family Coccidce includes the Scale-insects or Bark-lice, 

 Mealy-bugs, and certain other insects for which there are no popu- 

 lar names. In many respects this is a very anomalous group, the 

 species differing greatly in appearance, habits, and metamorphoses 

 from those of the most closely allied families. Not only do the 

 members of this family appear very unlike other insects, but there 

 is a wonderful variety of forms within the family ; and even the 

 two sexes of the same species differ as much in the adult state as 

 members of distinct orders. 



The males of Coccidae, unlike all other Hemiptera, undergo a 

 complete metamorphosis. The adult males have only a single pair 



*C6ccidae, Cficcus : coccum, "the berry that grows upon the scarlet oak." This sup- 

 posed berry was a bark-louse. 



