Insects and their world 



14. Isoptera (North America 45; world 1700) 



Termites: 'white ants'' (Fig. 7). True ants belong to the Order Hymen- 

 optera (28). * White ants' are a different Order of insects, quite un- 

 related, and the only similarity between them and true ants is that both 

 groups are social insects (see Chapter VI). This means that thousands of 

 individuals live together in a community, and are divided into castes. 

 Members of the various castes look different, and have different tasks to 

 perform in community life. 



One nest of termites may contain some thousands of individuals, and 

 their behaviour is complex, and highly organised. Some termites live in 

 living or dead wood above ground level, and often do a great deal of 

 hidden damage to buildings before they are discovered. Others make 

 elaborate nests in the soil, and may extend these above the level of the 

 ground, to form the great termitaria, or 'ant-hills' that are found in 

 tropical countries. 



Termites are among the few insects that can digest wood, doing this 

 with the help of Protozoa (single-celled organisms) in the intestine. 



Like the ants and the bees, the termites group their community round 

 an egg-laying female, called the queen. The queen termite has a normally- 

 sized head and thorax, but the abdomen is enlarged into a huge bag of 

 thin skin, packed with eggs (see Fig. 9). The organisation of a termi- 

 tarium is discussed more fully in Chapter VI. 



15. Psocoptera (North America 150; world iioo) 



Booklice; 'psocids'; barklice (Fig. 6). Very small, or even minute insects. 

 Those with wings are rather like aphids, but are distinguished by the 

 pattern of the wing-veins. The wingless ones are found indoors, and get 

 their name of 'booklice' because they are found among books and papers, 

 in cupboards, under loose wall-paper, and so on. They are believed to 

 feed on the moulds that grow in badly ventilated, damp places. Most of 

 the species of this Order live outdoors in places where moulds are present. 



Fig. 9. A queen termite. Order Isoptera. Note how the head and thorax 

 have remained normal in size, although the abdomen is distended with 



eggs 



14 



