Beetles 287 



spots. 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 their 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 

 which aphids or scale-insects are present. Sometimes they are deposited 

 in little patches right in the middle of a colony of plant-lice. The larvae 

 (Fig. 398) are elongate, widest across the prothorax and tapering back to 

 the tip, with the skin usually roughened or punctate, bearing hairs and short 

 spines, and marked with blackish, reddish, and yellowish. The larvae feed 

 steadily on the soft defenceless aphids or young scale-insects, or on the eggs 

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

 to the leaves or stems without entirely casting off the last larval exuvia (Fig. 

 398). This cuticle often surrounds the pupa "like a tight-fitting overcoat 

 with the front not closed by buttons." In other cases the larval skin is 

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

 end. 



The two-spotted ladybug, Adalia bipunctata, reddish yellow with a 

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

 enters houses to hibernate. The nine-spotted 

 ladybird, Coccinella novemnotata, has yellowish 

 elytra with four black spots on each in addition 

 to a common spot just behind the thorax. 

 The "twice-stabbed" ladybird, Chilocorus 

 bivulnerus, is shining black with a large red 

 spot on each elytron. Anatis i^-punctata, the 

 fifteen-spotted ladybird, is a large species with 

 dark brownish-red elytra bearing seven black 

 spots each, and a median common spot just 

 behind the thorax. FlG 3gg- _ A ladybird _ beetlej 



In California the ladybirds are of great Coccinella californica; larva, 



importance to the fruit-growers, their steady pupae ' and , dl ! lt on La 7 s . on 's 

 - cyprees. (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 



