PHYLUM ARTHROPODA 



363 



Some of the worst 

 pests are the locust 

 borer, Cyllcnc robinice, 

 the apple tree borer, 

 Saperda Candida, and 

 the sugar maple borer, 

 Plagionolus speciosus. 

 A common species, 

 Tetraopcs teiraophthal- 

 mus, is found on milk- 

 weed. 



SUBORDER 6. TRI- 

 MERA. (LADYBIRD 



BEETLES, Fig. 302.)- FIG. 302. Order COLEOPTERA. Novius cardi- 



The CorrTiSTFTTTD/F na ^ s > Australian ladybird beetle, feeding on the 



fluted scale, Icerya purchasi. a, ladybird larvae 

 or ladybird beetles, feeding on adult female and egg sac ; b, pupa ; 



arp nrpHarprms hntVi c - adult ladybird; d, orange twig, showing scale 

 drc ureudLeous. ijuin , , , ,. , , . /T -, ,, , , , 



and ladybirds natural size, (rrom Marlatt.) 



as larvae -and adults, 



feeding largely on plant-lice and scale-insects. They are conse- 

 quently beneficial since they help control these pests (see p. 347). 

 SUBORDER 7. HETEROMERA. (DARKLING, BLISTER- AND OIL- 

 BEETLES, Fig. 303.) - -The HETEROMERA contains the darkling 

 ground-beetles (TENEBRIONID.E) , one of which, the meal-worm, 



Tenebrio molitor (Fig. 303), 

 is quite common in mills 

 and grocery stores and is 

 used as food for cage 

 birds. This group also 

 includes the blister- and 

 oil-beetles (MELOID.E) ; 

 some of these when dried 







and pulverized have a 

 effect when 



FIG. 303. Order COLEOPTERA. Meal- blistering 



worm, Tenebrio molitor. A, larva. B, pupa. aDD li e( J to the human 

 C, adult. (From the Cambridge Natural 



History.) skin. 



