CLASSIFICATION OF INSECTS 311 



C. Beak evidently arising from head; tarsi three-jointed; antennae 



minute, bristlelike. 

 D. With three ocelli ; males with musical organs. Cicadas. (Page 



122) ClCADIDAE 



DD. With two ocelli or none ; males without musical organs. 

 E. Antennae inserted on sides of cheek beneath the eyes. 



FULGORIDAE 



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



F. Pronotum prolonged posteriorly over the abdomen or 

 at least over the scutellum. Tree-hoppers. (Page 124) 



MEMBRACIDAE 

 FF. Pronotum not prolonged above abdomen. 



G. Hind tibia armed with one or two stout teeth and 

 with short, stout spines at tip. Spittle-insects. (Page 



124) CERCOPIDAE 



GG. Hind tibia with two rows of spines. Leaf-hoppers. 



(Page 125) . JASSIDAE 



CC. Beak apparently arising from between the front coxae, or absent ; 



tarsi one- or two-jointed. 



D. Hind femora fitted for leaping ; antennae of nine or ten seg- 

 ments with two bristles on apex. Jumping plant-lice. (Page 



127) PSYLLIDAE 



DD. Hind femora normal ; antennae usually with less than ten 



segments. 

 E. Legs long and slender; wings transparent. Plant-lice. 



(Page 127) APHIDIDAE 



EE. Legs short ; wings usually opaque. 



F. Tarsus consisting of two joints ; body covered with a 

 whitish powder, male and female each with four wings. 



ALEYRODIDAE 



FF. Tarsus consisting of one joint ; adult male with two 

 wings ; female wingless, with the body scale-like or 

 gall-like in form. Scale insects. (Page 1 29) COCCIDAE 



KEY TO THE FAMILIES OF COLEOPTERA 



Head not prolonged into beak. (Coleoptera genuina.} 

 B. First and second tarsus consisting of five segments ; third tarsus con- 

 sisting of four segments Section HETEROMERA 



C. Head without distinct neck ; narrower than thorax and more or 

 less inserted in it; body wall hard. Darkling-beetles. (Page 165) 



TENEBRIONIDAE 

 CC. Head with distinct neck and as wide as prothorax ; body soft and 



elytra flexible. Blister-beetles - . . MELOIDAE 



BB. First, second, and third tarsi of same number of segments. 



