172 NATURE TEACHING. 



4. Beetles thus prove destructive both in 

 the larval and in the mature stage ; the)' feed 

 upon a great variety of substances, some bor- 

 ing in the stem, as the weevil borer in sugar- 

 cane or the cacao beetle in cacao trees, others 

 in tubers, as the sweet potato weevil, others 

 again in grain, stored foodstuffs, furniture and 

 even cigars and cigarettes. 



GRASSHOPPERS AND CRICKETS'. 



1. Another class of insects causing annoy- 

 ance to the cultivator includes the grasshop- 

 pers, crickets, etc. These insects differ from 

 those just referred to in that they do not pass 

 through a caterpillar or grub stage. The larvae, 

 when hatched from the eggs, are not unlike 

 the mature insect except that they are smaller 

 and do not possess wings ; wings are formed 

 gradually, and there is no resting pupal stage. 



2. The perfect insect has four wings, the 

 upper pair being leathery or parchment-like, 

 the lower ones being membranous ; the insects 

 have strong biting jaws. These insects feed 

 in all their stages, being active and voracious, 

 throughout their lives. They thus differ from 

 butterflies and beetles whose pupae are inactive 

 and do not feed. Some of these insects are very 

 destructive. Grasshoppers and crickets often 



