KEY TO THE OKDKl.'S 



287 



AA. Wings rudimentary or wanting. 

 B. Mouth prolonged into a beak. 



BB. Mouth not prolonged iuto a beak. 

 C. Tarsi five-jointed. 



Panorpidae. 



(Certain Scorpion-Flics.) 



CC. Tarsi four-jointed. 



Phri/gancidar. 

 (Certain Caddis-Flies.) 



Tcrmitiditc. 

 (Certain White Ants.) 

 CCC. Tarsi two- or three-jointed. 



D. Wings absent; or two rudimentary, leathery. 



Psocidae. 

 (Certain Book-Lice.) 



DD. Four rudimentary wings, veins visible. 



Perlidae. 



(Certain Stone-Flies.) 



CCCC. Tarsi one- or two- jointed. Mallophagidae. 



(Bird-Lice.) 



COLEOPTERA. 



A. Head not prolonged into a narrow beak, 

 B. Tarsi five-jointed. 



c. d. 



FIG 215. Various forms of antennfe of beetles, a, filiform, or thread-like ; 7>, 

 serrate, or saw-like ; e, pectinate, or comb-like ; d, lamellate, having an enlarged 

 end, composed of plates. 



C. Antenna? with terminal joints leaf-like (lamellifonn ; 

 i.e., broader and flatter than basal segments.) (Lamelli- 

 cornia.) 



D. The ventral surface of abdomen divided into five seg- 

 ments; elytra cover entire dorsal surface of abdomen; 



