OUK FRIENDS A.N'I) FOES 133 



pillars and kill them. The caterpillars become a " peri- 

 patetic banqueting-hall for unbidden guests." Then 

 there are others of this same group which lay eggs 

 among the eggs of injurious insects such as the codling 

 moth, and as their eggs hatch the young larva? sustain 

 themselves upon the eggs of these injurious forms. Of 

 these Hymenoptera there are no less than four that 

 prey upon the codling moth. 



The insect friends of the horticulturist are classed 

 under three heads : as pollenizers, as parasites upon in- 

 jurious forms, and as predaceous insects preying upon 

 injurious forms. The bee was an example of the first, 

 the ichneumon fly of the second, and chief among the 

 third might be mentioned the ladybirds or ladybugs, 

 about which there is the rhyme, 



"Ladybird, ladybird, fly away home : 

 Your house is on fire, your children will roam." 



Predaceous Insects. - These bright red beetles with 

 black spots on their backs are preeminently the friends 

 of the horticulturist. The 

 little immature forms known 

 as grubs or larva? spend their 

 time in eating up plant-lice, 

 scale insects, and many other 

 injurious forms. The adult 

 beetle is no less active. The 



most remarkable case on rec- ^ 107 - "L^yw.i" and larva, 



Coccinella abdominalis. 



ord of the beneficial results 



derived from a single insect is that of a member of 

 this group of ladybirds. A few years ago the 

 citrus or orange industries of California were al- 



