Beetles 287 



snots Their colors and markings make them conspicuous, and yet the 



natural enemies of insects, the birds, obviously let them alone; it is presumed, 



therefore, that these beetles are ill-tasting to birds, and that the.r bright colors 



are of the nature of readily perceived warning signs (see discussion of 



this subject in Chapter XVII). , , „ 



The eggs are laid on the bark, stems, or leaves of the tree or plant on 



^vhich aphfds or scale-insects are present. Sometimes they are deposited 



n 1 tie patches right in the middle of a colony of plant-hce. _ The larv. 



Fig ,98) are elongate, widest across the prothorax and tapenng back to 



the tip w th the skin usually roughened or punctate bearing hairs and short 



spnes and marked with blackish, reddish, and yellowish. The larva, feed 



S'y on the soft defenceless aphids or young scale-insects, or on the eggs 



and young of other larger insects. When full-grown they pupate, attach d 



to the leases or stems without entirely casting otf the last larval exuv.a (Fig 



; ) This cuticle often surrounds the pupa 'Mike a fght-htting overcoa 



^'th the front not dosed by buttons." In other cases the larval skin is 



forced backwards and remains as a little crumpled pad about the posterior 



'"%he two-spotted ladybug, Adalia bipunctata, reddish yellow with a 



singlblack spot on each elytron, is common in the East, where it often 



enters houses to hibernate. The nine-spotted 



ladybird, Coccinella nwemnoiata, has yellowish 



elytra with four black spots on each in addition 



to a common spot just behind the thorax. 



The "twice-stabbed" ladybird, Chilocorus 



hivulnerus, is shining black with a large red 



spot on each elytron. Anatis 15-punclata, the 



fifteen-spotted ladybird, is a large species with 



dark brownish-red elytra bearing seven black 



spots each, and a median common spot just 



bel'ind the thorax. Fig. 398. — A ladybird-beetle, 



"in California the ladybirds are of great ^-f f^', ""{rofLa.Ws 

 importance to the fruit-growers, their steady ^..precs. (Twice natural size.) 

 wholesale destruction of scale-insects being an . , • 



important factor in successful fruit-raising. Fig. 397 illustrates eight species 

 found on the Pacific coast. A number of ladybird species have been imported 

 from Australia and other countries from which numerous destructive scale- 

 insects had been earlier unwittingly brought on nursery stock. Most conspic- 

 uously successful of these attempts to introduce and disseminate original home 

 enemies of imported pests has been the establishment of the small red-and- 

 black ladybird, Vedalia cardinalis, which feeds exclusively on the fluted or cot- 

 tony cushion-scale (Icerya purchasi) (Fig. 254). This Australian scale first 



