290 



METAZOAN PHYLA 



destruction of plant lice and scale insects, both the larvae and adults 

 being eaten by them. The orange growers of California, when made 

 desperate by the ravages of a cottony scale insect which threatened ruin 

 to their orange groves, were able to overcome the pest by the help of 

 ladybirds imported from Australia (Fig. 188). Here also are to be con- 

 sidered the burying and the carrion beetles, which bury or destroy dead 

 animals and organic matter which might otherwise prove offensive. 



The order Neuroptera (nu rop' ter a; G., neuron, nerve, and 'pteron, 

 wing) includes the lace-winged flies, sometimes called aphis lions because 

 the larvae, as well as the adults, feed on plant lice. Their eggs are laid 





«;t: 



^m% 



■^ •I^^^^I^^S^Sva^isvy^i* 



B 



Fig. 189. — Ant lion, Myrmeleon sp. A, larva, X 2. B, pit, with concealed larva, 

 X %. C, adult, slightly enlarged. {A and C from Kellogg, "American Insects," by the 

 courtesy of Henry Holt & Company; B, original.) 



on plants and mounted on a long stalk, which insures immunity from the 

 attacks of enemies. The order also includes the ant lions, the larvae of 

 which live in the ground, concealed at the bottom of conical pits (Fig. 189). 

 They feed upon insects which when running over the ground fall into 

 these pits. The victim slides to the bottom of the pit, where it is seized 

 by the ant-lion larva and sucked dry, after which the body is thrown clear 

 of the pit by a jerk of the head of the captor. The pits are excavated 

 by the throwing out of the grains of earth in a similar fashion and natur- 

 ally are found only in loose, sandy soil. They are also placed under 

 overhanging ledges of rock or under vegetation where they are protected 

 from rain. Frequently many occur within a small area. The pits 

 increase in size with the growth of the larva until they reach a diameter 

 of from two to three inches. 



