54 ARTHROPODS 



DD. Prothorax prolonged into a horn or point above the 



abdomen Membracidae. 



AA. Beak apparently arising from between the front legs, or ab- 

 sent; tarsi one or two jointed; antennae usually prominent and 

 thread like, sometimes wanting. 



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

 C. Wings transparent. 

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



Psyllidae. 

 DD. Legs long and slender, not fitted for leaping; antennae 



three to seven jointed Aphididae. 



BB. Tarsi one-jointed; adult male without any beak, and with 

 only two wings ; female wingless, with the body either scale- 

 like or gall-like in form, or grublike 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 Coccidae. 



THE BEETLE 



Harpalus caliginosus 



General Features. — How does the covering of this ani- 

 mal differ from that of the insects previotisly studied? Can 

 you find the three divisions of the body frorii the dorsal 

 side? From the ventral? Do you think this animal is 

 fitted for the life it leads? In what ways? Draw longi- 

 tudinal and lateral axes. 



The Head. — (i) Look on the dorsal side of the head 

 for eyes. How many? What kind? Is there any signifi- 

 cance in their position? On the dorsal side find also the 

 lahrum and the tips of the mandibles. How do the man- 

 dibles compare with the mandibles of other insects. 



