146 CLASS-BOOK OF ZOOLOGY. 



603. Of what use are Vein-winged Insects ? 



604. How are Oak-balls and other excrescences of plants produced ? 



605. How are those punctures made ? 



606. Describe the Ovipositor. 



607. What Insects contribute materially to the destruction of Caterpit 

 lars, and how ? 



608. For what are Wasps, Hornets, Bees, and Ants remarkable ? 



609. Of what individuals is a hive of Bees composed? 



610. Describe the Queen Bee, the Drones, and Working Bees. 



611. What do you know of the young of Bees? 



612. Describe their sting. 



613. Of what does the food of Bees consist ? 



614. How do Bees collect the pollen? 



615. How do they prepare the honey and wax? 



616. How do experienced Bee-raisers treat their Bees? 



617. Into what social classes are Ants divided? 



618. What do you know of their eggs and metamorphosis? 



619. Of what does their food consist? 



620. At what time are the winged Males and Females seen, and what 

 happens to them? 



621. Where are Ants found, and for what is the White Ant celebrated 1 



SECTION XXXVIII. 



6th Order — Two-winged Insects : (Diptera.) 



§ 622. Among two-winged Insects are iucluded all kinds 

 of Flies which are provided with only two wings. Some 

 of them have a hard-pointed sucking-tube ; others, an elon- 

 gated snout, (proboscis,) and others again, simply a 

 mouth. 



§ 623. Their larva is a Maggot, of a white color, of the 

 form of a spindle, and is found in water, dung, spoiled 

 meat, cheese, and fruit. 



§ 624. The Maggot grows very rapidly, its color changes 

 to brown after a few days, its skin becomes hard, and it 

 is soon converted into a Puppa, (cocoon ;) from this, which 

 resembles a barrel in its shape, proceeds the perfect Fly. 



§ 625. Many species of Flies look like insects of other 

 orders. Thus the Sheep-fly resembles a Spider, and 



