THEIR RELATION TO EACH OTHER 89 



stage; the body being more or less ovate, set with 

 lateral tubercles giving rise to groups of bristles, while 

 the mandibles are long, slender and pointed, peculiar 

 in being grooved on the inner side so that the body 

 juices of the prey may run down through them into the 

 mouth cavity. The Chrysopidce are known as Aphis- 

 lions, and when they capture a plant louse it is held 

 up, impaled on the mandibles, until the juices are all 



Fig. 36. — A lace-wing fly, Chrysopa oculata- a, eRgs on stalks; b, larva; d. same 

 feeding on pear psylla; e. the cocoon from which /. the adult, has escaped. 



absorbed; then the dry carcass is thrown away. The 

 Myrmeleonidce or ant-lions build a pit in the sand to 

 entrap any unwary insect that may come along, and 

 anything that does come is seized in the same way and 

 exhausted, the empty shell being thrown out later. 

 Not all ant-lions build pits and not all the members of 

 the families named agree in all respects with the general 

 statements as to larval form and characters; but for 

 the majority of the species that come under observa- 

 tion they are correct. 



