20 



EXTERNAL STRUCTURE OF INSECTS 



plant behind it. Locusts and grasshoppers lay their eggs in the 

 soil, and fall plowing generally serves to keep our native forms in 

 check. 



Order Coleoptera ("sheath-winged"). This name refers to 

 the fact that the insects of this group have the fore wings hardened 

 and horny, or modified to form covers for the second pair of wings, 

 the true wings, when they are present. They have biting mouth 



parts, and a complete 

 metamorphosis. The 

 group includes the 

 beetles. The potato 

 beetle (" potato bug"), 

 most of our wood 

 borers, the May beetle 

 which comes from the 

 white grub, blister 



FIG. 23. A ground beetle. 



FIG. 24. A buprestid beetle. 



beetles, plum curculio, weevils, and many others occur here (Figs. 

 23 and 24). 



Order Hymenoptera ("membrane- winged"). Members of this 

 group of insects have four membranous wings with but few veins 

 therein. The front wings are the larger. Mouth parts adapted for 

 biting and sucking. The abdomen of the female is usually fur- 



