BENEFICIAL INSECTS 71 



throve in the balmy California climate, and particularly well 

 probably because they had left all their native enemies far be- 

 hind. By 1880 they had spread to the great orange-growing 

 districts of southern California, five hundred miles away, and 

 in the next ten years caused enormous loss to the growers. 

 In 1888 the entomologist Koebele, recommended by the gov- 

 ernment division of entomology, was sent at the expense of the 

 California fruit growers to Australia to try to find out and send 

 back some effective predaceous or parasitic enemy of the pest. 



Fig. 47. — Parasitic Insects. 

 A, parasitic Ichneumon fly laying eggs in the cocoon of a tent caterpillar; B, 

 parasitic tachina fly ; C, part of an army worm with tachina fly eggs attached 

 to it. (After Fiske.) 



As a result of this effort, a few Vedalias (Fig. 46) were sent to 

 California, where they were zealously fed and cared for, and soon, 

 after a few generations, enough of the little beetles were on hand 

 to warrant trying to colonize them in the attacked orange groves. 

 With astonishing and gratifying success the Vedalia in a very 

 few years had so naturally increased and spread that the ruth- 

 less scale was definitely checked in its destruction, and from 

 that time to this has been able to do only occasionally and in 

 limited localities any injury at all." 



Parasitic Insects. — Parasitic insects (Fig. 47) are those that 



