SICKING INSECTS. 175 



flies about, being thus entirely different in 

 habit and appearance from the full grown 

 female ; the male insects are very small and 

 are not often seen unless specially looked for. 



4. The scale-insects often cause a great 

 amount of damage, as the plants attacked by 

 them frequently die. In this way they are 

 a source of much anxiety to West Indian 

 fruit-growers, particularly to cultivators of 

 oranges and limes which often suffer seriously 

 from their ravages. 



5. Mention should be made of bees and 

 wasps. These insects have four membranous 

 wings, their larvae are grub-like and their pupae 

 inactive. Most of the insects of this class possess 

 a sting, which either serves for defensive pur- 

 poses, or is fashioned into an apparatus by 

 means of which the eggs are placed in the 

 animal or vegetable tissues in which the insect 

 deposits them. 



6. Distinguished from the insects already 

 mentioned, all of which have four wings, are 

 the flies, which only possess two. The larvae 

 usually called maggots are footless grubs with 

 an undefined head ; they are thus distinguish- 

 able from the grubs of beetles. The pupae 

 are inactive and often resemble brown seeds. 



